Gold plating

Electroforrning, which is used in the production of art objects or jewelry is a combination of electroless plating and electro deposition. A wax mold of the object to be produced is made conductive by electroless gold plating, a thick layer of gold or gold alloy is then electrodeposited and, finally, the wax is removed by melting (134). 

Plate Thickness. Thickness of the plate should always be specified as should the locations on the work where the thickness is to be measured. Generally, thicker deposits perform better, but there are notable exceptions. Mating parts, eg, fasteners having fine machine threads, are not usable if over plated. Machine-threads are usually plated to 10 p.m or less, depending on tolerances. Additionally, gold-plate over nickel does not solder well if too thick thus, gold is usually 1—2 pm or less. Chromium, plated for decorative purposes from the conventional chromic acid bath, tends to macrocrack above about 0.7—1.0 pm. 

Patent 3,384,154, May 21, 1968). Both of these tubes also had steam-side coatings to promote dropwise condensation—paryleue for tube 47 and gold plating for tube 39. 

Cylinders are typieally proteeted from over-pressurization by frangible gold-plated dises and fusible plugs. 

The basic goal of quality management is the elimination of failure both in the concept and in the reality of our products, services, and processes. In an ideal world, if we could design products, services, and processes that could not fail we would have achieved the ultimate goal. Failure means not only that products, services, and processes would fail to fulfill their function but that their function was not what our customers desired. A gold-plated mousetrap that does not fail is not a success if no one needs a gold-plated mousetrap ... 

Nickel-plated copper/gold-plated copper... 

Copper/silver-plated copper Solder-dipped copp>er/tin-plated aluminium Copper/tin-plated copper Copper/solder-dipped copper Copper/reflowed tinned copper Silver-plated copper/tin-plated copper Silver-plated copper/solder-dipped copper Gold-plated copper/tin-plated copper Aluminium/tin-plated aluminium (zincate process)... 

Gold-plated copper/solder-dipped copper Tin-plated aluminium/nickel-plated copper Aluminium/solder-dipped aluminium... 

Aluminium/brass Aluminium/copper Tin-plated aluminium/copper Aluminium/nickel-plated copper Aluminium/nickel-plated brass Aluminium/silver-plated copper Tin-plated aluminium/silver-plated copper Aluminium/gold-plated copper Tin-plated aluminium/gold-plated copper... 

Fig. 13.1 Log/log plot of gold-plate porosity against thickness for the conventional hot-cyanide gold-plating bath on copper substrate. The porosity was determined by the amount of copper (p.p.m.) dissolved under standard conditions by an ammonia-ammonium persulphate...

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