Test results show that inte-rface reaction between W-clading and diamond occur at between 700～1250℃,the epitaxial islands of WC and W_2C are formed and grow on the diamond su-rface,therfore metallurgical bond of interface between diamond and copperaclloy is achieved.

The effect of Tungsten on the microstructure of Ni-W alloy coatings prepared by the pulse electrodeposition technology is firstly investigated by X-ray Diffraction.

Ni-W alloy coatings are prepared by pulse electrodeposition.

Ni-W alloy coatings with excellent hardness, wear resistance and appearance produced by electrodeposition were introduced in this dissertation.

A new Ni-Fe-W alloy coatings were obtained by pulse electrodeposition,the effect of W in the electrolyte contents on the structure of coatings,and the effect of the electrolyte contents on the hardness and thickness of coatings were discussed.

Then,the effects of the concentration of NiSO_4·6H_2O、Na_2WO_4·2H_2O、FeSO_4·7H_2O and temperature on the quality of Ni-Fe-W alloy coatings are also addressed.

Study on the properties of Ni-W-P alloy coating;

The test results show that the Ni-W-P alloy coatings adhere to the substrate very well and have no pore when coating thickness reaches 15μm.