The Analogue Nt is a home video game console designed and manufactured by Analogue , designed to play games for the Nintendo Entertainment System and the Famicom.
78-511: In March, 2014 the system was announced. Analogue began accepting pre-orders for the system on May 5, 2014. Pre-orders began shipping in June 2015. A limited run of 10 24 karat gold plated special edition systems were produced by April 2016, and were available for sale at a price of $ 4999. In 2016 Analogue announced a followup system, the Nt Mini , a smaller model which includes RGB & HDMI output in
156-404: A DC power source (such as a cathodic protection rectifier ). Anodes for ICCP systems are tubular and solid rod shapes of various specialized materials. These include high silicon cast iron , graphite, mixed metal oxide or platinum coated titanium or niobium coated rod and wires. Anodic protection impresses anodic current on the structure to be protected (opposite to the cathodic protection). It
234-454: A pit or crack, or it can extend across a wide area, more or less uniformly corroding the surface. Because corrosion is a diffusion -controlled process, it occurs on exposed surfaces. As a result, methods to reduce the activity of the exposed surface, such as passivation and chromate conversion , can increase a material's corrosion resistance. However, some corrosion mechanisms are less visible and less predictable. The chemistry of corrosion
312-606: A 4/5, praising the graphical output of the system as "simply the best-looking direct feed of an NES cartridge I've ever seen.", while noting that the price of the console with HDMI output was "tough-to-swallow". Vice praised the Analogue Nt's build quality and video quality saying, "the Analogue Nt is a gorgeous machine...The Analogue Nt makes NES games look phenomenal.", while also noting that NES games may have limited appeal to gamers not nostalgic for them. CNET.com said "In an age where retro games just don't look right on modern HDTVs,
390-410: A barrier to further oxidation. The chemical composition and microstructure of a passive film are different from the underlying metal. Typical passive film thickness on aluminium, stainless steels, and alloys is within 10 nanometers. The passive film is different from oxide layers that are formed upon heating and are in the micrometer thickness range – the passive film recovers if removed or damaged whereas
468-408: A calcareous deposit, which will help shield the metal from further attack. Metal dusting is a catastrophic form of corrosion that occurs when susceptible materials are exposed to environments with high carbon activities, such as synthesis gas and other high-CO environments. The corrosion manifests itself as a break-up of bulk metal to metal powder. The suspected mechanism is firstly the deposition of
546-495: A few micrometers across, making it even less noticeable. Crevice corrosion is a localized form of corrosion occurring in confined spaces (crevices), to which the access of the working fluid from the environment is limited. Formation of a differential aeration cell leads to corrosion inside the crevices. Examples of crevices are gaps and contact areas between parts, under gaskets or seals, inside cracks and seams, spaces filled with deposits, and under sludge piles. Crevice corrosion
624-481: A given alloy's ability to re-form a passivating film. In the worst case, almost all of the surface will remain protected, but tiny local fluctuations will degrade the oxide film in a few critical points. Corrosion at these points will be greatly amplified, and can cause corrosion pits of several types, depending upon conditions. While the corrosion pits only nucleate under fairly extreme circumstances, they can continue to grow even when conditions return to normal, since
702-461: A graphite layer on the surface of the metal, usually from carbon monoxide (CO) in the vapor phase. This graphite layer is then thought to form metastable M 3 C species (where M is the metal), which migrate away from the metal surface. However, in some regimes, no M 3 C species is observed indicating a direct transfer of metal atoms into the graphite layer. Various treatments are used to slow corrosion damage to metallic objects which are exposed to
780-474: A part or structure fails . Pitting remains among the most common and damaging forms of corrosion in passivated alloys, but it can be prevented by control of the alloy's environment. Pitting results when a small hole, or cavity, forms in the metal, usually as a result of de-passivation of a small area. This area becomes anodic, while part of the remaining metal becomes cathodic, producing a localized galvanic reaction. The deterioration of this small area penetrates
858-449: A result of heating. This non-galvanic form of corrosion can occur when a metal is subjected to a hot atmosphere containing oxygen, sulfur (" sulfidation "), or other compounds capable of oxidizing (or assisting the oxidation of) the material concerned. For example, materials used in aerospace, power generation, and even in car engines must resist sustained periods at high temperature, during which they may be exposed to an atmosphere containing
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#1732877240339936-568: A slower rate. When immersed separately, each metal corrodes at its own rate. What type of metal(s) to use is readily determined by following the galvanic series . For example, zinc is often used as a sacrificial anode for steel structures. Galvanic corrosion is of major interest to the marine industry and also anywhere water (containing salts) contacts pipes or metal structures. Factors such as relative size of anode , types of metal, and operating conditions ( temperature , humidity , salinity , etc.) affect galvanic corrosion. The surface area ratio of
1014-521: A smooth surface. For example, phosphoric acid may also be used to electropolish copper but it does this by removing copper, not the products of copper corrosion. Some metals are more intrinsically resistant to corrosion than others (for some examples, see galvanic series ). There are various ways of protecting metals from corrosion (oxidation) including painting, hot-dip galvanization , cathodic protection , and combinations of these. The materials most resistant to corrosion are those for which corrosion
1092-471: A uniform potential, the driving force for the corrosion reaction is halted. For galvanic CP systems, the anode material corrodes under the influence of the steel, and eventually it must be replaced. The polarization is caused by the current flow from the anode to the cathode, driven by the difference in electrode potential between the anode and the cathode. The most common sacrificial anode materials are aluminum, zinc, magnesium and related alloys. Aluminum has
1170-458: A wave of claims due to pipe failures. Most ceramic materials are almost entirely immune to corrosion. The strong chemical bonds that hold them together leave very little free chemical energy in the structure; they can be thought of as already corroded. When corrosion does occur, it is almost always a simple dissolution of the material or chemical reaction, rather than an electrochemical process. A common example of corrosion protection in ceramics
1248-605: A working perspective, sacrificial anodes systems are considered to be less precise than modern cathodic protection systems such as Impressed Current Cathodic Protection (ICCP) systems. Their ability to provide requisite protection has to be checked regularly by means of underwater inspection by divers. Furthermore, as they have a finite lifespan, sacrificial anodes need to be replaced regularly over time. For larger structures, galvanic anodes cannot economically deliver enough current to provide complete protection. Impressed current cathodic protection (ICCP) systems use anodes connected to
1326-511: Is thermodynamically unfavorable. Any corrosion products of gold or platinum tend to decompose spontaneously into pure metal, which is why these elements can be found in metallic form on Earth and have long been valued. More common "base" metals can only be protected by more temporary means. Some metals have naturally slow reaction kinetics , even though their corrosion is thermodynamically favorable. These include such metals as zinc , magnesium , and cadmium . While corrosion of these metals
1404-407: Is a technique to control the corrosion of a metal surface by making it the cathode of an electrochemical cell . Cathodic protection systems are most commonly used to protect steel pipelines and tanks; steel pier piles , ships, and offshore oil platforms . For effective CP, the potential of the steel surface is polarized (pushed) more negative until the metal surface has a uniform potential. With
1482-451: Is appropriate for metals that exhibit passivity (e.g. stainless steel) and suitably small passive current over a wide range of potentials. It is used in aggressive environments, such as solutions of sulfuric acid. Anodic protection is an electrochemical method of corrosion protection by keeping metal in passive state The formation of an oxide layer is described by the Deal–Grove model , which
1560-501: Is calculated as where k is a constant, W is the weight loss of the metal in time t , A is the surface area of the metal exposed, and ρ is the density of the metal (in g/cm ). Other common expressions for the corrosion rate is penetration depth and change of mechanical properties. In 2002, the US Federal Highway Administration released a study titled "Corrosion Costs and Preventive Strategies in
1638-404: Is called a galvanic series and is useful in predicting and understanding corrosion. Often, it is possible to chemically remove the products of corrosion. For example, phosphoric acid in the form of naval jelly is often applied to ferrous tools or surfaces to remove rust. Corrosion removal should not be confused with electropolishing , which removes some layers of the underlying metal to make
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#17328772403391716-624: Is complex; it can be considered an electrochemical phenomenon. During corrosion at a particular spot on the surface of an object made of iron, oxidation takes place and that spot behaves as an anode . The electrons released at this anodic spot move through the metal to another spot on the object, and reduce oxygen at that spot in presence of H (which is believed to be available from carbonic acid ( H 2 CO 3 ) formed due to dissolution of carbon dioxide from air into water in moist air condition of atmosphere. Hydrogen ion in water may also be available due to dissolution of other acidic oxides from
1794-421: Is continuous and ongoing, it happens at an acceptably slow rate. An extreme example is graphite , which releases large amounts of energy upon oxidation , but has such slow kinetics that it is effectively immune to electrochemical corrosion under normal conditions. Passivation refers to the spontaneous formation of an ultrathin film of corrosion products, known as a passive film, on the metal's surface that act as
1872-399: Is influenced by the crevice type (metal-metal, metal-non-metal), crevice geometry (size, surface finish), and metallurgical and environmental factors. The susceptibility to crevice corrosion can be evaluated with ASTM standard procedures. A critical crevice corrosion temperature is commonly used to rank a material's resistance to crevice corrosion. In the chemical industry , hydrogen grooving
1950-447: Is often deposited on the copper substrate before the gold plating. The layer of nickel provides mechanical backing for the gold layer, improving its wear resistance. It also reduces the impact of pores present in the gold layer. Both the nickel and gold layers can be plated by electrolytic or electroless processes. There are many factors to consider in selection of either electrolytic or electroless plating methods. These include what
2028-419: Is often used in electronics, to provide a corrosion -resistant electrically conductive layer on copper , typically in electrical connectors and printed circuit boards . With direct gold-on-copper plating, the copper atoms tend to diffuse through the gold layer, causing tarnishing of its surface and formation of an oxide and/or sulphide layer. A layer of a suitable barrier metal , usually nickel ,
2106-461: Is one of the most common causes of bridge accidents. As rust displaces a much higher volume than the originating mass of iron, its build-up can also cause failure by forcing apart adjacent components. It was the cause of the collapse of the Mianus River Bridge in 1983, when support bearings rusted internally and pushed one corner of the road slab off its support. Three drivers on the roadway at
2184-406: Is the corrosion of piping at grooves created by the interaction of a corrosive agent, corroded pipe constituents, and hydrogen gas bubbles . For example, when sulfuric acid ( H 2 SO 4 ) flows through steel pipes, the iron in the steel reacts with the acid to form a passivation coating of iron sulfate ( FeSO 4 ) and hydrogen gas ( H 2 ). The iron sulfate coating will protect
2262-479: Is used in the manufacture of jewellery . The thickness of gold plating on jewellery is noted in microns (or micro-meters). The microns of thickness determines how long the gold plating lasts with usage. The jewellery industry denotes different qualities of gold plating in the following terminology Gold plated silver jewellery can still tarnish as the silver atoms diffuse into the gold layer, causing slow gradual fading of its color and eventually causing tarnishing of
2340-400: Is used to predict and control oxide layer formation in diverse situations. A simple test for measuring corrosion is the weight loss method. The method involves exposing a clean weighed piece of the metal or alloy to the corrosive environment for a specified time followed by cleaning to remove corrosion products and weighing the piece to determine the loss of weight. The rate of corrosion ( R )
2418-620: The AuSn 4 compound. Particles of AuSn 4 disperse in the solder matrix, forming preferential cleavage planes, significantly lowering the mechanical strength and therefore reliability of the resulting solder joints. If the gold layer does not completely dissolve into the solder, then slow intermetallic reactions can proceed in the solid state as the tin and gold atoms cross-migrate. Intermetallics have poor electrical conductivity and low strength. The ongoing intermetallic reactions also cause Kirkendall effect , leading to mechanical failure of
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2496-457: The United States of America . Casing could be anodized red, blue, or black for an additional fee. The system dimensions are 1.7 by 9.7 by 5.7 inches (43 mm × 246 mm × 145 mm). The Analogue Nt received positive reviews, with critics praising performance on HD TVs , while noting an unusually high price for the system. Will Greenwald's PCMag review gave the Analogue Nt
2574-416: The grain boundaries of stainless alloys. This chemical reaction robs the material of chromium in the zone near the grain boundary, making those areas much less resistant to corrosion. This creates a galvanic couple with the well-protected alloy nearby, which leads to "weld decay" (corrosion of the grain boundaries in the heat affected zones) in highly corrosive environments. This process can seriously reduce
2652-549: The lockout chip used on the NES. The system was designed to be compatible with NES, Famicom, and Famicom Disk System titles. The default model was released with RGB (RGB, Component , S-Video , Composite , VGA , and SCART ) video outputs, with an additional "add-on" for 1080p HDMI output and other digital features. The Analogue Nt's enclosure is solid aluminium unibody enclosure manufactured from 6061 aluminium in China , and assembled in
2730-408: The Analogue Nt is a magical piece of hardware." while noting that "At $ 500 the Analogue Nt is obviously not for everyone." The high price of the system was noted by many, such as Kyle Orland of Ars Technica , who noted that "it's hard to recommend to anyone besides the most committed 8-bit retro gaming addict". Gold plating Gold plating is a method of depositing a thin layer of gold onto
2808-584: The United States" on the direct costs associated with metallic corrosion in the US industry. In 1998, the total annual direct cost of corrosion in the US roughly $ 276 billion (or 3.2% of the US gross domestic product at the time). Broken down into five specific industries, the economic losses are $ 22.6 billion in infrastructure, $ 17.6 billion in production and manufacturing, $ 29.7 billion in transportation, $ 20.1 billion in government, and $ 47.9 billion in utilities. Rust
2886-406: The anode and cathode directly affects the corrosion rates of the materials. Galvanic corrosion is often prevented by the use of sacrificial anodes . In any given environment (one standard medium is aerated, room-temperature seawater ), one metal will be either more noble or more active than others, based on how strongly its ions are bound to the surface. Two metals in electrical contact share
2964-423: The atmosphere). This spot behaves as a cathode . Galvanic corrosion occurs when two different metals have physical or electrical contact with each other and are immersed in a common electrolyte , or when the same metal is exposed to electrolyte with different concentrations. In a galvanic couple , the more active metal (the anode) corrodes at an accelerated rate and the more noble metal (the cathode) corrodes at
3042-411: The base model and uses an FPGA as a processor. By July 23, 2017, the Analogue Nt had been discontinued. Instead of software emulation or an FPGA , the original Analogue Nt uses parts sourced from damaged Famicom HVC-001 systems. In particular the system incorporates a Ricoh 2A03 CPU and an NTSC Ricoh 2c02 PPU, on a custom printed circuit board. A notable original chip which was omitted included
3120-434: The bridge at the time. Similarly, corrosion of concrete-covered steel and iron can cause the concrete to spall , creating severe structural problems. It is one of the most common failure modes of reinforced concrete bridges . Measuring instruments based on the half-cell potential can detect the potential corrosion spots before total failure of the concrete structure is reached. Until 20–30 years ago, galvanized steel pipe
3198-483: The corrosion resistance substantially. Alternatively, antimicrobial-producing biofilms can be used to inhibit mild steel corrosion from sulfate-reducing bacteria . Controlled permeability formwork (CPF) is a method of preventing the corrosion of reinforcement by naturally enhancing the durability of the cover during concrete placement. CPF has been used in environments to combat the effects of carbonation , chlorides, frost , and abrasion. Cathodic protection (CP)
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3276-420: The deposit will be used for, configuration of the part, materials compatibility and cost of processing. In different applications, electrolytic or electroless plating can have cost advantages. At higher frequencies, the skin effect may cause higher losses due to higher electrical resistance of nickel; a nickel-plated trace can have its useful length shortened three times in the 1 GHz band in comparison with
3354-432: The deposits of corrosion products, leading to localized corrosion. Accelerated low-water corrosion (ALWC) is a particularly aggressive form of MIC that affects steel piles in seawater near the low water tide mark. It is characterized by an orange sludge, which smells of hydrogen sulfide when treated with acid. Corrosion rates can be very high and design corrosion allowances can soon be exceeded leading to premature failure of
3432-443: The electronics industry: Soldering gold-plated parts can be problematic as gold is soluble in solder . Solder which contains more than 4–5% gold can become brittle. The joint surface is dull-looking. Gold reacts with both tin and lead in their liquid state, forming brittle intermetallics . When eutectic 63% tin – 37% lead solder is used, no lead-gold compounds are formed, because gold preferentially reacts with tin, forming
3510-475: The environment is controlled (especially in recirculating systems), corrosion inhibitors can often be added to it. These chemicals form an electrically insulating or chemically impermeable coating on exposed metal surfaces, to suppress electrochemical reactions. Such methods make the system less sensitive to scratches or defects in the coating, since extra inhibitors can be made available wherever metal becomes exposed. Chemicals that inhibit corrosion include some of
3588-513: The form of compacted oxide layer glazes , prevent or reduce wear during high-temperature sliding contact of metallic (or metallic and ceramic) surfaces. Thermal oxidation is also commonly used to produce controlled oxide nanostructures, including nanowires and thin films. Microbial corrosion , or commonly known as microbiologically influenced corrosion (MIC), is a corrosion caused or promoted by microorganisms , usually chemoautotrophs . It can apply to both metallic and non-metallic materials, in
3666-411: The grain boundaries. Special alloys, either with low carbon content or with added carbon " getters " such as titanium and niobium (in types 321 and 347, respectively), can prevent this effect, but the latter require special heat treatment after welding to prevent the similar phenomenon of "knifeline attack". As its name implies, corrosion is limited to a very narrow zone adjacent to the weld, often only
3744-403: The highest capacity, and magnesium has the highest driving voltage and is thus used where resistance is higher. Zinc is general purpose and the basis for galvanizing. A number of problems are associated with sacrificial anodes. Among these, from an environmental perspective, is the release of zinc, magnesium, aluminum and heavy metals such as cadmium into the environment including seawater. From
3822-419: The interface with the metal that leads to the buildup of an electronic barrier opposing electron flow and an electronic depletion region that prevents further oxidation reactions. These results indicate a mechanism of "electronic passivation". The electronic properties of this semiconducting oxide film also provide a mechanistic explanation of corrosion mediated by chloride , which creates surface states at
3900-560: The interior and causing extensive damage even while the outer protective layer remains apparently intact for a period of time. Plating , painting , and the application of enamel are the most common anti-corrosion treatments. They work by providing a barrier of corrosion-resistant material between the damaging environment and the structural material. Aside from cosmetic and manufacturing issues, there may be tradeoffs in mechanical flexibility versus resistance to abrasion and high temperature. Platings usually fail only in small sections, but if
3978-500: The interior of a pit is naturally deprived of oxygen and locally the pH decreases to very low values and the corrosion rate increases due to an autocatalytic process. In extreme cases, the sharp tips of extremely long and narrow corrosion pits can cause stress concentration to the point that otherwise tough alloys can shatter; a thin film pierced by an invisibly small hole can hide a thumb sized pit from view. These problems are especially dangerous because they are difficult to detect before
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#17328772403394056-401: The joint, similar to the degradation of gold-aluminium bonds known as purple plague . A 2–3 μm layer of gold dissolves completely within one second during typical wave soldering conditions. Layers of gold thinner than 0.5 μm (0.02 thou ) also dissolve completely into the solder, exposing the underlying metal (usually nickel) to the solder. Impurities in the nickel layer can prevent
4134-418: The long-lasting performance of this group of materials. If breakdown occurs in the passive film due to chemical or mechanical factors, the resulting major modes of corrosion may include pitting corrosion , crevice corrosion , and stress corrosion cracking . Certain conditions, such as low concentrations of oxygen or high concentrations of species such as chloride which compete as anions , can interfere with
4212-433: The mechanical strength of welded joints over time. A stainless steel is said to be "sensitized" if chromium carbides are formed in the microstructure. A typical microstructure of a normalized type 304 stainless steel shows no signs of sensitization, while a heavily sensitized steel shows the presence of grain boundary precipitates. The dark lines in the sensitized microstructure are networks of chromium carbides formed along
4290-474: The metal and can lead to failure. This form of corrosion is often difficult to detect due to the fact that it is usually relatively small and may be covered and hidden by corrosion-produced compounds. Stainless steel can pose special corrosion challenges, since its passivating behavior relies on the presence of a major alloying component ( chromium , at least 11.5%). Because of the elevated temperatures of welding and heat treatment, chromium carbides can form in
4368-484: The metal coating thickness. Painting either by roller or brush is more desirable for tight spaces; spray would be better for larger coating areas such as steel decks and waterfront applications. Flexible polyurethane coatings, like Durabak-M26 for example, can provide an anti-corrosive seal with a highly durable slip resistant membrane. Painted coatings are relatively easy to apply and have fast drying times although temperature and humidity may cause dry times to vary. If
4446-439: The metal's oxide film. These pores allow the oxide to grow much thicker than passivating conditions would allow. At the end of the treatment, the pores are allowed to seal, forming a harder-than-usual surface layer. If this coating is scratched, normal passivation processes take over to protect the damaged area. Anodizing is very resilient to weathering and corrosion, so it is commonly used for building facades and other areas where
4524-504: The most common use of the word, this means electrochemical oxidation of metal in reaction with an oxidant such as oxygen , hydrogen, or hydroxide. Rusting , the formation of red-orange iron oxides, is a well-known example of electrochemical corrosion. This type of corrosion typically produces oxides or salts of the original metal and results in a distinctive coloration. Corrosion can also occur in materials other than metals, such as ceramics or polymers , although in this context,
4602-497: The non-plated one. Selective plating is used, depositing the nickel and gold layers only on areas where it is required and does not cause the detrimental side effects. Gold plating may lead to formation of gold whiskers . Wire bonding between gold plated contacts and aluminium wires or between aluminium contacts and gold wires under certain conditions develops a brittle layer of gold-aluminium intermetallics , known as purple plague . There are several types of gold plating used in
4680-435: The oxide deposits. Carbon is another nickel contaminant that hinders solderability. Corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide . It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion. In
4758-465: The oxide layer does not. Passivation in natural environments such as air, water and soil at moderate pH is seen in such materials as aluminium , stainless steel , titanium , and silicon . Passivation is primarily determined by metallurgical and environmental factors. The effect of pH is summarized using Pourbaix diagrams , but many other factors are influential. Some conditions that inhibit passivation include high pH for aluminium and zinc, low pH or
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#17328772403394836-407: The oxide surface that lead to electronic breakthrough, restoration of anodic currents, and disruption of the electronic passivation mechanism. Passivation is extremely useful in mitigating corrosion damage, however even a high-quality alloy will corrode if its ability to form a passivating film is hindered. Proper selection of the right grade of material for the specific environment is important for
4914-413: The plating is more noble than the substrate (for example, chromium on steel), a galvanic couple will cause any exposed area to corrode much more rapidly than an unplated surface would. For this reason, it is often wise to plate with active metal such as zinc or cadmium . If the zinc coating is not thick enough the surface soon becomes unsightly with rusting obvious. The design life is directly related to
4992-450: The potentially highly-corrosive products of combustion. Some products of high-temperature corrosion can potentially be turned to the advantage of the engineer. The formation of oxides on stainless steels, for example, can provide a protective layer preventing further atmospheric attack, allowing for a material to be used for sustained periods at both room and high temperatures in hostile conditions. Such high-temperature corrosion products, in
5070-630: The presence of chloride ions for stainless steel, high temperature for titanium (in which case the oxide dissolves into the metal, rather than the electrolyte) and fluoride ions for silicon. On the other hand, unusual conditions may result in passivation of materials that are normally unprotected, as the alkaline environment of concrete does for steel rebar . Exposure to a liquid metal such as mercury or hot solder can often circumvent passivation mechanisms. It has been shown using electrochemical scanning tunneling microscopy that during iron passivation, an n-type semiconductor Fe(III) oxide grows at
5148-415: The presence or absence of oxygen. Sulfate-reducing bacteria are active in the absence of oxygen (anaerobic); they produce hydrogen sulfide , causing sulfide stress cracking . In the presence of oxygen (aerobic), some bacteria may directly oxidize iron to iron oxides and hydroxides, other bacteria oxidize sulfur and produce sulfuric acid causing biogenic sulfide corrosion . Concentration cells can form in
5226-473: The salts in hard water (Roman water systems are known for their mineral deposits ), chromates , phosphates , polyaniline , other conducting polymers , and a wide range of specially designed chemicals that resemble surfactants (i.e., long-chain organic molecules with ionic end groups). Aluminium alloys often undergo a surface treatment. Electrochemical conditions in the bath are carefully adjusted so that uniform pores, several nanometers wide, appear in
5304-407: The same electrons, so that the "tug-of-war" at each surface is analogous to competition for free electrons between the two materials. Using the electrolyte as a host for the flow of ions in the same direction, the noble metal will take electrons from the active one. The resulting mass flow or electric current can be measured to establish a hierarchy of materials in the medium of interest. This hierarchy
5382-400: The solder from bonding to it. Electroless nickel plating contains phosphorus. Nickel with more than 8% phosphorus is not solderable. Electrodeposited nickel may contain nickel hydroxide . An acid bath is required to remove the passivation layer before applying the gold layer; improper cleaning leads to a nickel surface difficult to solder. A stronger flux can help, as it aids dissolving
5460-401: The steel from further reaction; however, if hydrogen bubbles contact this coating, it will be removed. Thus, a groove can be formed by a travelling bubble, exposing more steel to the acid, causing a vicious cycle . The grooving is exacerbated by the tendency of subsequent bubbles to follow the same path. High-temperature corrosion is chemical deterioration of a material (typically a metal) as
5538-466: The steel pile. Piles that have been coated and have cathodic protection installed at the time of construction are not susceptible to ALWC. For unprotected piles, sacrificial anodes can be installed locally to the affected areas to inhibit the corrosion or a complete retrofitted sacrificial anode system can be installed. Affected areas can also be treated using cathodic protection, using either sacrificial anodes or applying current to an inert anode to produce
5616-475: The surface of another metal, most often copper or silver (to make silver-gilt ), by a chemical or electrochemical ( electroplating ) process. Plating refers to modern coating methods, such as the ones used in the electronics industry , whereas gilding is the decorative covering of an object with gold, which typically involve more traditional methods and much larger objects. There are five recognized classes of gold plating chemistry: Gold plating of silver
5694-475: The surface will come into regular contact with the elements. While being resilient, it must be cleaned frequently. If left without cleaning, panel edge staining will naturally occur. Anodization is the process of converting an anode into cathode by bringing a more active anode in contact with it. A new form of protection has been developed by applying certain species of bacterial films to the surface of metals in highly corrosive environments. This process increases
5772-636: The surface. This process may take months and even years, depending on the thickness of the gold layer. A barrier metal layer is used to counter this effect; these can be nickel or rhodium. Copper, which also migrates into gold, does so more slowly than silver. The copper is usually further plated with nickel. A gold-plated silver article is usually a silver substrate with layers of copper, nickel, and gold deposited on top of it. Gold, applied by evaporated methods or electroplating, has been specified by NASA to thermally control spacecraft instruments, due to its 99.4% reflectivity in infrared wavelengths. Gold plating
5850-494: The term "degradation" is more common. Corrosion degrades the useful properties of materials and structures including mechanical strength, appearance, and permeability to liquids and gases. Corrosive is distinguished from caustic: the former implies mechanical degradation, the latter chemical. Many structural alloys corrode merely from exposure to moisture in air, but the process can be strongly affected by exposure to certain substances. Corrosion can be concentrated locally to form
5928-555: The time died as the slab fell into the river below. The following NTSB investigation showed that a drain in the road had been blocked for road re-surfacing, and had not been unblocked; as a result, runoff water penetrated the support hangers. Rust was also an important factor in the Silver Bridge disaster of 1967 in West Virginia , when a steel suspension bridge collapsed within a minute, killing 46 drivers and passengers who were on
6006-527: The weather, salt water, acids, or other hostile environments. Some unprotected metallic alloys are extremely vulnerable to corrosion, such as those used in neodymium magnets , which can spall or crumble into powder even in dry, temperature-stable indoor environments unless properly treated. When surface treatments are used to reduce corrosion, great care must be taken to ensure complete coverage, without gaps, cracks, or pinhole defects. Small defects can act as an " Achilles' heel ", allowing corrosion to penetrate
6084-426: Was used extensively in the potable water systems for single and multi-family residents as well as commercial and public construction. Today, these systems have long ago consumed the protective zinc and are corroding internally, resulting in poor water quality and pipe failures. The economic impact on homeowners, condo dwellers, and the public infrastructure is estimated at $ 22 billion as the insurance industry braces for
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