Flame spray wire process | corrosion resistant coating | hvof coatings

Flame Spray Powder

Introduction

Flame spraying is primarily used to apply abradable coatings or nickel/chrome self-fluxing alloys which are subsequently heat treated to metallurgically bond them to the substrate (Fused coatings).

Main Applications

Abradable coatings are used for machine element clearance in compressors.

Fused coatings are extensively used in high wear applications such as mining and steel industries to prevent wear of rolls, pistons and other equipment in aggressive wear environments.

This table is a guide to the range of metals available, their properties and typical applications

Process Description

A Flame Spray gun uses oxygen and fuel gases to produce a flame into which powder is injected. The resultant molten particles of powder are projected on to the workpiece to produce the coating.

Many coatings sprayed by this process are then heat treated at around 1000ºC to 'fuse' the coatings to the substrate surface.

Fused coatings produced by this process are hard and corrosion resistant and are able to withstand wear by abrasion, fretting, cavitation and other hard surfaces.

The addition of different proportions of carbon, silicon and boron to the basic nickel/chromium alloy results in the formation of hard phases of carbides, silicide and borides.

They can be applied 1 - 5 mm thick; much thicker than hard wear coatings applied by the plasma or HVOF processes.