Manufacture of Nonmagnetic Wc Based Cemented Carbide Using Pre-Solution Treatment of Nickel and Ammonium Paratungstate

An effective technique for making nonmagnetic WC based cemented carbide by using Ni(W) solid solution manufactured from ammonium paratungstate (APT) as the binder was developed. It was found that powder particles using APT as the W source had larger contact area between W and Ni and higher activity, which was conducive to the mutual diffusion between Ni and W, leading to a faster solid phase reaction and higher content of W diffused into Ni. The value of magnetic saturation (Ms) of Ni(W) solid solution powders using APT as the tungsten source was nearly zero under an suitable diffusion condition (550 ×2 h +800×2 h in hydrogen), much lower than that when using W powder. And the nonmagnetic property of WC based cemented carbide derived from nonmagnetic Ni(W) solid solution as the binder was much better than those derived from pure Ni as the binder.