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Multiple Contaminant Gas Effects on Electronic Equipment Corrosion
Abstract
The reliability of electronic/electrical devices may be greatly affected by the presence of certain airborne gaseous contaminants. Copper and silver coupons in environmentally controlled chambers were exposed to hydrogen sulfide (H2S), sulfur dioxide (SO2), chlorine (Cl2), and nitrogen dioxide (NO2). The coupons were exposed to the four single gases and combinations thereof, and corrosion levels were subsequently determined by cathodic/electrolytic reduction. On the copper coupons, H2S produced the dominant corrosive effects. For the silver coupons, the combination H2S + NO2 showed a powerful synergy that produced up to five times the expected corrosion.
... as the "realistic worst case" concentration (i.e., 10 ppb and 2 ppb for H 2 S and Cl 2 , respectively) for data centers. These are lower than the maximum values suggested in ASHRAE 175-TRP (1400 ppb and 10 ppb for H 2 S and Cl 2 , respectively), but are sufficiently high to cause significant corrosion based on previous laboratory tests (Muller, 1991). Based on the results of the literature review and assuming that indoor concentrations would be similar to the outdoor level in a worst condition when outdoor air are used directly for free cooling, a "realistic indoor worst-case concentration" for MFGs testing of corrosion were defined as follows: 60 ppb O 3 , 80 ppb NO 2 , 40 ppb SO 2 , 2 ppb Cl 2 and 10 ppb H 2 S (Zhang et al. 2019). ...
... Gaseous contaminants which are transported between the gas regime and liquid regime causes different pollutant concentrations in the liquid regime, which affects the corrosion rate of materials (Graedel, Franey, and Kammlott 1984). A higher air velocity can increase the corrosion rate until it reaches a level (about 0.03 m/s) above which the corrosion rate levels off when the mass transfer is no longer a limiting process (Muller 1991). Many investigations have made the experiments under different temperature and relative humidity conditions, which included temperature from 21 C to 80 C, relative humidity from 15% to 90% and pollutant concentrations: >50ppb O 3 , 29-4600 ppb SO 2 , 128-4900 ppb NO 2 , 1.9-10 ppb Cl 2 and <10 ->1000 ppb H 2 S (Mohan, Sundaram, and Guruviah 1991;Muller 1991;Graedel, Franey, and Kammlott 1984;Vernon 1931;Eriksson, Johansson, and Standberg 1993;Backlund et al. 1966;Feliu et al. n.d.;Franey, Kammlott, and Graedel 1985;Aastrup et al. 2000). ...
... A higher air velocity can increase the corrosion rate until it reaches a level (about 0.03 m/s) above which the corrosion rate levels off when the mass transfer is no longer a limiting process (Muller 1991). Many investigations have made the experiments under different temperature and relative humidity conditions, which included temperature from 21 C to 80 C, relative humidity from 15% to 90% and pollutant concentrations: >50ppb O 3 , 29-4600 ppb SO 2 , 128-4900 ppb NO 2 , 1.9-10 ppb Cl 2 and <10 ->1000 ppb H 2 S (Mohan, Sundaram, and Guruviah 1991;Muller 1991;Graedel, Franey, and Kammlott 1984;Vernon 1931;Eriksson, Johansson, and Standberg 1993;Backlund et al. 1966;Feliu et al. n.d.;Franey, Kammlott, and Graedel 1985;Aastrup et al. 2000). Chloride, nitrogen dioxide, ozone and sulfur dioxide are the common corrosive gases for atmospheric corrosive agents. ...
The effects of moisture content, temperature and pollutant mixture on atmospheric corrosion of copper and silver were investigated by exposing test specimens to different environmental conditions, followed by surface characterization using the coulometric reduction, Scanning Electron Microscopy and Energy Dispersive Spectrometry (SEM/EDS). Printed circuit board test cards (PCBs) with bare copper were also used to investigate the effects of voltage bias on the PCBs on the corrosion rate. The test specimens were exposed to mixed flowing gases (MFG) environment with 8 different combinations of the following five pollutants at the fixed concentration levels: 60 ppb O3, 80 ppb NO2, 40 ppb SO2, 2 ppb Cl2 and 10 ppb H2S. Temperature and relative humidity were varied from a reference condition (21°C and 50% RH which is within the current ASHRAE-recommended thermal envelope) to a higher value (28°C, 70% RH or 80% RH) to effect the moisture content of the test environment. The test results revealed the dominating effect of Cl2 on copper corrosion and that of H2S on silver corrosion. Increasing the moisture content at 21°C caused more severe corrosion for copper when Cl2 was present, but not for silver. When temperature was increased from 21°C to 28°C at 50% RH, it reduced the corrosion on copper, but not on silver. Voltage biased PCBs had a less effect on corrosion than PCBs without the bias. These results could be used for possible expansion of the ASHRAE-recommended thermal envelope for data centers when Cl2 and H2S are not present, and limit the thermal envelope when Cl2 or H2S are present.
... The combination of H 2 S and NO 2 has proven to be harmful for many pure metals. For instance, it has been demonstrated that the corrosion resulting from the sulfidation of silver and copper is increased at high NO 2 concentrations [41]. Finally, NO 2 and SO 2 may be another corrosive mixture of pollutants for the pure metals contained in solar reflectors. ...
... The final damage level after 21 days for the combined tests proves that the ranking of aggressiveness coincides with the one of single-gas tests, but in all gas mixtures the degradation of materials is accelerated, indicating a synergy between the studied gases, as reported in previous publications [39][40][41][42]. According to Fig. 9, for the three H 2 S tests (blue, green and purple squares), the highest ΔW occurs at the beginning of the tests (between 0 and 4 days), and then the ΔW tendency is to stabilize over time. ...
... However, the highest ΔW (up to 900 μm) is achieved after the Test H 2 S + NO 2 (purple squares), which is in agreement with previous results that stated the increasing sulfidation rate of silver at high NO 2 concentrations in the presence of H 2 S in dry air [39]. Furthermore, the mixture of H 2 S and NO 2 provokes higher corrosion than the single-gas tests [41]. Additionally, the other tests with NO 2 (orange and red triangles) present similar ΔW after 21 days, although the mixture of NO 2 +SO 2 (orange triangles) implies a slightly higher ΔW than only NO 2 (red triangles), showing the effect of SO 2 molecules. ...
Concentrating solar thermal technologies have experienced an important boost in the last few years. Besides the production of electricity, they are particularly useful for the supply of industrial process heat. The industrial atmospheres affecting these solar plants typically contain gaseous pollutants that are likely to promote corrosion on the components of the solar facility, specifically solar reflectors, thereby compromising their optimal performance and the overall system efficiency. Seven accelerated aging tests were designed to study the effects of three air pollutants (H2S, SO2 and NO2) on the durability of two commercially available reflector types (silvered-glass and aluminum), both in single-gas tests and in multicomponent gas mixtures. Additionally, the same material types were exposed outdoors at five representative polluted sites, including industrial, urban and coastal environments. Reflectance and optical microscope monitoring corroborated which degree of corrosion was developed on a specific type of reflector in the different tests with gaseous pollutants, as well as the synergistic effects of gas combinations. For example, tests with sulfur were harmful for silvered-glass reflectors (up to a total of 16 corrosion spots), whereas aluminum was particularly affected by tests with NO2 (numerous micro spots of around 50 μm size). Moreover, comparisons of the corrosion patterns found in accelerated-aging and outdoor exposures revealed which laboratory test reproduced the different real polluted atmospheres in the most realistic way, which is the main goal of this work. For instance, the degradation found at Site 2 was reproduced by Test NO2+SO2, with an acceleration factor of 27.
... Reactivity monitoring is a convenient and quantitative method to determine the corrosive potential of an environment by measuring the total corrosion film thickness on specially prepared copper coupons. Some studies [137,138] using "laboratory and field-exposed coupons have shown that using copper coupons alone can significantly under or overstate this corrosive potential". This method exposes coupons to the environment for 30 days and the resulting corrosion product thickness is evaluated by using coulometric reduction and chemistry. ...
... On the other hand, using Silver alone also has its limitation when used alone because it is more sensitive to Chlorine. Therefore, it is important to use corrosion classification coupons using both copper and silver for accurate results for environmental classifications [138]. The use of Combination Corrosion Classification (CCC) coupons as adopted in these experiments using both Copper and Silver was then proposed as the most accurate classification of an environment. ...
Over the last decade, several hyper-scale data center companies such as Google, Facebook, and Microsoft have demonstrated the cost-saving capabilities of airside economization with direct/indirect heat exchangers by moving to chiller-less air-cooled data centers. Under pressure from data center owners, IT equipment OEMs like Dell and IBM are developing IT equipment that can withstand peak excursion temperature ratings of up to 45°C, clearly outside the recommended envelope, and into ASHRAE's A4 allowable envelope. As popular and widespread as these cooling technologies are becoming, airside economization comes with its challenges. There is a risk of pre-mature hardware failures or reliability degradation posed by uncontrolled fine particulate and gaseous contaminants in presence of temperature and humidity transients. This paper presents an in-depth review of the particulate and gaseous contamination-related challenges faced by the modern-day data center facilities that use airside economization. This review summarizes specific experimental and computational studies to characterize the airborne contaminants and associated failure modes and mechanisms. In addition, standard lab-based and in-situ test methods for measuring the corrosive effects of the particles and the corrosive gases, as the means of testing the robustness of the equipment against these contaminants, under different temperature and relative humidity conditions are also reviewed. It also outlines the cost-sensitive mitigation techniques like improved filtration strategies and methods that can be utilized for efficient implementation of airside economization.
... Moreover, the transformer copper wires are tinned that provides some initial protection to electronic. The fatigue cracks start growing in the thin tin layer which exposure bare copper in wires to the sulfur containing corrosive environment [5][6][7][8][9]. ...
Green corrosion inhibitors used for protection of metals and alloys in electronic devices
are a key interest area for researcher because of increased environmental awareness
which restrict the use of toxic and hazardous corrosion inhibitors which contaminate our
ecological system. Advancement of green chemical technologies towards novel vaporphase
corrosion inhibitors (VPCI) as green inhibitors for electronics corrosion and their
adsorption mechanism is discussed in detail here. Also, the protective role of VPCI for
various metals and alloys used in electronics components and industrial applications are
discussed.
... Conversely, aluminium has been proven to be more reactive when exposed to marine environments containing chlorides and to atmospheres with sulphur dioxide [22,23]. Much research has been focused on the effects that industrial air atmospheres may have on electrical contact materials under laboratory accelerated conditions [24,25]. Consequently, a great number of experiments combining different corrosive gases were designed and applied to silver and copper, and their correspondent reaction products were analysed. ...
The degradation of reflector materials for concentrating solar thermal applications is analysed. Corrosion of their metallic reflective layer is considered a major problem in facilities which are located near industrial sites, where reduced sulphur gases may be present. Accelerated ageing tests were performed to study the influence of H2S on the corrosion of two types of silvered glass reflectors and one aluminium reflector. Different degradation patterns were found for silvered glass reflectors, whereas aluminium reflectors did not corrode in the presence of the sulphurous gas. Therefore, industrial pollution caused by this type of gas may decrease the solar collectors' performance.
Corrosion costs more than a trillion dollars worldwide and with great efforts being made
to solve this problem. The toxic effect of components used in the solution of this problem
causes new problems with increasing environmental concerns and high costs.
Accordingly, green inhibitors have become an alternative protection method with its
ecofriendly nature. With the development of green chemistry technologies, the role of
plant extracts and biowastes as new corrosion inhibitors in various environments and
their protection effect for many materials have been determined. In this study, besides
these mentioned topics, test methods, corrosion prevention mechanisms, and economic
approaches are summarized.
The reliability of electrical/electronic equipment in corrosive environments must be accurately gauged to avoid equipment failure. It has become apparent that using a standard employing copper-only testing is inadequate for this purpose. Field-exposed CCCs have shown that environments considered noncorrosive by current (copper) standards can be extremely corrosive to other functional materials. It is shown that the use of copper, silver, and gold coupons for assessing the corrosive potential of an environment gives a more complete picture of what is actually occurring in that environment. Results obtained from these CCCs can show types of contaminants present and can be used to help develop the proper control strategies.
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