Patent ID: 7833581

Claim:
A method of depositing a stable diamond film, the method comprising: providing a metal substrate; pretreating a surface of the substrate and then placing the substrate in a reaction chamber; depositing a diamond film on the substrate by way of an N-stage chemical vapor deposition to form a stable composite comprising the diamond film on the substrate, the depositing step comprising: increasing the substrate temperature from a starting temperature (ST) to a first stage temperature (T 1 ) in a set period of time (ti 1 ), keeping the substrate at the first stage temperature (T 1 ) for a period of working time (t 1 ) while at least diamond is deposited on the pretreated surface of the substrate, then for each n-th stage of N−1 subsequent further stages, further increasing the substrate temperature to an n-th stage temperature (T n ) in a further set period of time (ti n ); and further keeping the substrate at the n-th stage temperature (T n ) for a further period of working time (t n ) while at least diamond is deposited; and then cooling the substrate and the diamond film during a period of cooling time (t f ), the stable composite comprising the substrate and the diamond film, wherein N, the number of stages, is selected from the range of 3 to 10, wherein n, the stage index, increases from 3 to N, wherein T 1 and t 1 are together selected to produce a dense, thin distribution of a carbide of metal of the metal substrate, wherein T N and t N corresponding to the final, Nth, stage are together selected to produce a diamond layer having a crystal size of less than 2 μm, and wherein a T n and a t n are together selected to produce a layer of diamond and nondiamond carbon which adhesively joins the carbide layer with superficial diamond.