Uniform diamond coatings on WC-Co hard alloy cutting inserts deposited by a microwave plasma CVD

TL;DR

This study demonstrates the successful deposition of uniform diamond coatings on WC-Co cutting inserts using microwave plasma CVD, leading to significantly improved cutting performance and wear resistance.

Contribution

It introduces a novel plateholder design for uniform diamond coating on complex substrates and optimizes process parameters for enhanced tool performance.

Findings

Uniform diamond coatings achieved with optimized process.

Cutting force and wear resistance reduced by a factor of two.

Cutting efficiency increased by 4.3 times.

Abstract

Polycrystalline diamond coatings have been grown on cemented carbide substrates with different aspect ratios by a microwave plasma CVD in methane-hydrogen gas mixtures. To protect the edges of the substrates from non-uniform heating due to the plasma edge effect, a special plateholder with pockets for group growth has been used. The difference in heights of the substrates and plateholder, and its influence on the diamond film mean grain size, growth rate, phase composition and stress was investigated. The substrate temperature range, within which uniform diamond films are produced with good adhesion, is determined. The diamond-coated cutting inserts produced at optimized process exhibited a reduction of cutting force and wear resistance by a factor of two, and cutting efficiency increase by 4.3 times upon turning A390 Al-Si alloy as compared to performance of uncoated tools.