Gold Plating Tests

Test method for porosity in gold platings on metal substrates by gas exposures Test method for half-cell potentials of uncoated reinforcing steel in concrete Method for detection of copper corrosion from petroleum products by the copper strip tarnish test... 

Gold Chloride Test To a few ml of 1% aqueous solution of hyoscyamine acidified with hydrochloric acid, add a few drops of gold chloride solution a lemon oily precipitate is formed which crystallizes after a while. The precipitate is recrystallized from boiling water acidified with diluted hydrochloric acid, and dried. The aurichloride of hyoscyamine so formed appears as golden yellow hexagonal plates, has a melting point of 165. ... 

With the use of a quartz filter in front of the PUF22 the possible presence of dust in the test chambers was investigated. 50 m chamber air were sucked through the filter. The filter was weighed before and after under the same climate conditions and no dust was found gravimetrically. Even on a special gold-plated filter (nucleopore) which is normally used for determination of asbestos in air there was no detection of dust particles with an electron microscope. 

Specimens for microscopy were obtained from the bonded specimens and from the samples after the D 905 tests. For transverse sections, samples were water-soaked for 2-24 h prior to microtoming. The sections were analyzed using a scanning electron microscope (JEOL 840 after gold plating the samples) or a Leitz Orthoplan epi-fluorescence microscope with a 150-W mercury lamp light source, an A2 UV filter cube, and a Nikon DS-5M digital camera, or a Carl Zeiss Axioskop epi-fluorescence microscope with a 100-W mercury lamp, a UV filter set, and CCD camera. Fluorescence microscopy was used to examine the failure surface. 

In addition to the scientific program, the workshop had its share of cultural activities. There was an impressive traditional drum show on the spot. One afternoon was devoted to a visit in a gold craft workshop, where participants had a chance to test gold plating. There was also a visit to a zen temple, where they could discuss with zen monks and practice meditation for a few hours. The award ceremony of the CMOA Prize and Medal took place in the banquet room of the Kanazawa Excel Hotel Tokyu. 

Electrical-stability testing is essential for conductive adhesives used for electrical connections. Electrical conductivity can degrade at elevated temperatures, on aging with or without power, and on exposiue to humidity and temperature. The specific test method used depends on the application. One test used for die-attach adhesives specified in NASA MSFC-SPEC-592 (now inactive) involves a series of gold-plated Kovar tabs attached with conductive epoxy to metal pads on an interconnect substrate. In the test vehicle, a bias of 5 V and cmrent density of 139 3.9 A7cm (900 A/in ) are applied to a series of wire-connected tabs, and the resistance change is measured after exposure to 150 °C periodically up to 1,000 horns. The maximum allowable resistance change is 5%. 

IPC aging tests on all surface materials that come in contact with adhesives. Bond-joint resistance is measured by depositing a strip of adhesive 1 in x 0.5 in (minimum) onto gold-plated stainless steel and then applying a second gold-plated stainless-steel strip to give a one-half inch overlap. ... 

Fig. 13.2 Linear plots of the effect of current density on the porosity, expressed as p.p.m. Cu, for three different gold-plating baths. The numbers next to each point show the actual average thickness /im) for each test. Bath A was a proprietary alkaline cyanide bath using silver as a brightener. Bath D was an acid gold bath containing cobalt and an ethylenediamine tetraacetic...

Differences of opinion have existed for decades with respect to the mixture of corrosive gases that should be used in test chambers. For air-conditioned electronic equipment rooms in urban environments that are well removed from industrial pollution (Class II Battelle environment, G1 IBM environment, and lEC Class II environment), the appropriate Battelle accelerated life test calls for use of 200 ppb NO2, 10 ppb H2S, and 10 ppb CI2 at an RH of 70 %. This test does an excellent job of simulating corrosion films on silver, copper, tin, and some gold-plated metals, but has been criticized in recent years because the Aims it produces on nickel are unrealistic. 

Two tests [2] are used to determine the porosity of gold contacts used in outdoor equipment (1) a nitric acid vapor test (exposure of gold-plated specimens in a desiccator containing 300 mL nitric acid for 1 h at 24 3°C and a maximum relative humidity of 60 %) tmd (2) an alkaline polysulfide test (the specimen is immersed for 60 s in a solution made of sodium sulfide, water, and excess flower of sulfur, filtered and diluted to a specific gravity of 1.142, and made alkaline with sodium hydroxide). 

The rate of rise to maximum wetting force This will show the level of oxides present on the surface in the case of a gold-plated part, and how thick the deposit is. This again will provide information on process control and/or age and storage of the parts being tested. 

The formation of (II) provides a quite selective spot test for palladium. Gold must be removed prior to the test because it will cause the development of a deep ruby red in the spot plate test and a diffused violet spot on the paper, apparently due to the reduction of the gold ions to the colloidal metal. Interference may also arise from 0s04 , Os+, Ru+, and RuCle ions because they have distinct self-colors. Mercurous ion causes partial interference by the reduction of part of the palladium to the elementary state, but a positive response can still be seen. It is possible to detect I part of palladium in the presence of 200 parts of platinum or 100 parts of rhodium. Less favorable ratios should be avoided because of the color of these salts. No interference is caused by mercuric and iridic chloride, but free ammonia, ammonium ions, stannous, cyanide, thiocyanate, fluoride, oxalate, and tetraborate ions do interfere. Lead, silver, ferrous, ferric, stannic, cobaltous, nickel, cupric, nitrite, sulfate, chloride, and bromide ions do not interfere. 

Testing. The uniaxial deformation measurements were carried out in a dynamometer (Instron, model 3366) at 25 °C, and at a cross-head speed of 500 mm/min. Strains from 0 to 750% were performed. All specimens were stretched by the movable clamp until the elongation of interest was achieved. Subsequently, each sample was held at the fixed extension, and glued either to a gold-plated electrode for BDS measurements or to a metallic frame for the X-ray scattering experiments. The strained sample-electrode assembly was then separated from the dynamometer clamps. 

The stability of the electrical parameters after ageing at high temperature under power is of prime importance in the selection of die attach adhesives. The test requires a current density of 139.5 A cm applied to five gold-plated Kovar tabs, each tab being adhesively bonded to thin film gold conductors and series bonded with gold wires. The biased test specimens are heated at 150°C in nitrogen for 1000 h, and the electrical resistance of the bonds is measured at 25°C at 200 h intervals. The specification requirement states that the resistance of the five tabs does not increase more than 5%. 

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