Studies on electroless nickel boride coating on boron carbide particles

Abstract

Ni-B alloy deposits were successfully formed over alkali surface treated boron carbide by electroless technique and the effects of processing parameters such as reduction bath pH, temperature and post-heat treatment were investigated. Microstructural studies show remarkable changes in structural morphology from mesh-like structure to platelet type Ni-B coating. The main Ni-B phases observed were NiB, Ni 2 B, Ni 3 B and Ni 4 B 3 . An effective Ni-B alloy coating with better surface characteristics was formed at pH 8 under 75uC reaction bath temperature in the presence of bath stabiliser. The post-heat treatment of Ni-B coated particles under varying bath reaction temperatures at 400uC showed remarkable Ni-B phase transformation from metastable NiB and Ni 2 B to stable crystalline Ni 3 B phase. The NiB coated particle shows lower particle-matrix interfacial reaction, better wettability and enhanced dispersion in aluminium composites compared to uncoated particles.

Recent advances in electroless nickel‑boron coatings

“…EN-P-based processes are once again more popular for the production of core-shell particles containing nickel alloys by electroless plating, but some nickel-boron core-shells have been reported as early as the late 90th [8,340]. Several types of particles have been used as core: boron carbides (B 4 C) [341][342][343][344][345][346], diamond [347], titanium [348], silicon carbide [349], magnesium oxide [350] and titanium hydride [351]. In most cases, a pre-treatment consisting of sensitization and activation is made on the powders to increase their catalytic activity.…”

“…Boron carbide is the third hardest material known after diamond and boron nitride and has excellent properties: good chemical resistance, low density, excellent thermomechanical and electrochemical properties, neutron adsorption, etc. that allow its use in various application fields such as diamond tools, hot-pressed shot blast nozzles, tooling dies, armors, nuclear reactor and-so-forth… However, it suffers from low toughness, poor wettability, and sinterability that make the manufacturing of high-density B 4 C parts challenging, which is why the addition of a metallic layer by electroless coating offers significant advantages for these materials [342,345,[352][353][354][355]. B 4 C particles coated with EN-B have been consolidated by liquid phase sintering at 1600 • C. No nickel diffusion was found into the bulk B 4 C, but boron and carbon have diffused into the EN-B layer [353,354].…”

A study of laser cladding NiCrBSi/Mo composite coatings

“…Cracks and pores are major obstacles to the development of laser cladding technology. In this regard, many scholars at home and abroad have effectively explored this issue, and they have made some progress [11][12][13].…”

Effect of SiC particle morphology on Co–P electroless coating characteristics

“…It provides a means for metallic coating of ceramic reinforcement without the requirement for costly electrolytic bath or other electroplating equipment and associated electrical running costs. [1][2][3][4][5][6][7][8][9][10][11][12] In the past few decades, many research works have been carried out on electroless plating of Cu 2,3,5,8,11 and Ni 1,6,7,10 on ceramic particles, carbon nanotubes and fibres to increase the wettability of the reinforcement phase with molten aluminium. Such coatings could also avoid the detrimental formation of weak phases between the reinforcement and the matrix material.…”