This study evaluates the anti-icing properties of flame-sprayed polyethylene (PE) coatings. In laboratory scale icing tests, thermally sprayed polymer coatings showed low ice adhesion compared to metals such as aluminum and stainless steel. The ice adhesion of flame-sprayed PE coatings was found to be roughly seven times lower than that of bulk aluminium and five times lower than that of bulk stainless steel.

A new process called in-mold metal spraying (IMMS) shows good potential for producing metallized plastic parts quickly and inexpensively. A zinc layer is deposited on mold cavity inserts using wire arc spraying and subsequently transferred to a plastic carrier via injection molding. Finely adjusted bonding strength between the carrier body and coating is essential for successful coating transfer. To that end, this study evaluates the influence of carrier body surface pretreatments on the transferability and bonding strength of zinc coating. Carrier bodies made of different types of steel pretreated by glass bead blasting and EDM were tested and their surface topography examined. In the initial experiments, the hardness and surface topography of carrier bodies were identified as factors that can influence coating transferability. Further experiments focusing on the adhesion strength of zinc on hardened and annealed carrier bodies were conducted to verify the influence of hardness on bonding strength.

This paper presents key findings from an ongoing study on the marine corrosion behavior of thermally sprayed zinc and aluminum coatings. Zn, Al, and Zn-Al layers of varied thickness were applied to twelve steel pipes by arc and flame spraying and subjected to different post-spray treatments such as sealing and painting. The pipes are mounted vertically on a test rig in the Pacific Ocean and have been inspected annually to record the appearance and thickness of the coatings. After 7 years, the Zn coatings began to show signs of degradation in the immersed portion of the pipe, although no such changes occurred with Al and Zn-Al coatings. After 18 years, heavily damaged sections of three pipes were removed and new pipe was welded in place. The repaired regions were coated with Al-5%Mg, which has performed well so far.

This paper discusses the different types of rolls used in paper machines, the functions and performance required of them, and recent improvements achieved with the aid of thermal spray coatings. It presents examples showing how metal and ceramic coatings applied by HVOF and plasma spraying have reduced operating expenses and extended roll life by stabilizing and improving various surface properties.

Alumina and chromia coatings were deposited on steel substrates by detonation spraying in order to determine the effect of spray parameters on adhesion, hardness, porosity, and dielectric strength. Test results show that both coatings have low porosity, high hardness, and good adhesion strength and that both can be effective as wear-resistant electrically insulating layers on metal parts.

In this study, FeCr coatings with different percentages of chromium were deposited on Grade 91 steel substrates by HVOF spraying, followed by aluminum enrichment via pack cementation. Overaluminizing parameters were optimized to prevent changes in the substrate microstructure, making it possible to determine the role of Cr and the effect of Al enrichment on anticorrosion behavior. The combination of HVOF spraying and pack cementation are shown to be adequate techniques for depositing intermediate and top layers in protective coating systems.

This paper presents a new approach to overcome arc plasma instabilities in suspension plasma spraying. The method employs a dc plasma torch with a large cathode cavity. This design modification reduces the Helmholtz frequency of the torch, resulting in a new oscillation mode with a very regular voltage signal. In the experiments, droplets of a TiO 2 suspension are injected into the pulsed laminar arc jet in synch with the Helmholtz resonant frequency. Interactions between the plasma and droplets are observed by time-resolved imagine techniques and are discussed.