July_August_AMP_Digital

iTSSe TSS A D V A N C E D M A T E R I A L S & P R O C E S S E S | J U L Y / A U G U S T 2 0 1 9 5 3 iTSSe TSS JTST HIGHLIGHTS Their in-flight particle velocities were measured using a cold spray meter and the impact temperatures and velocities were simulated. Using fixed spraying conditions consisting of a He bond coat and a nitrogen buildup step, 3-4-mm-thick coatings were produced and tested for bond strength. Coating cross sections and fracture surfaces of selected coatings were exam- ined. These trials confirm that although the various powder sizes tested produce dense and sound coatings, tight control of particle size distributions is required to achieve optimal im- pact velocities that ensure deformation of the steel and good coating adhesion (Fig. 2). Fig. 2 — Spraying fixture features circular “puck” coupons to be used for characterization and adhesion testing. BEYOND TRADITIONAL COATINGS: A REVIEW ON THERMAL-SPRAYED FUNCTIONAL AND SMART COATINGS D. Tejero-Martin, M. Rezvani Rad, A. McDonald, and T. Hussain The aim of this paper is to present a comprehensive re- view of the current state of functional and smart coatings pro- duced using thermal spraying deposition. It first describes the different thermal spraying technologies with a focus on how 13 different techniques achieve the thermal andkinetic energy re- quired to forma coating. It also focuses on the environment to which feedstock particles are exposed in terms of temperature and velocity. It first deals with state-of-the-art functional and smart coatings applied using thermal spraying techniques; a discussion follows on the fundamentals on which the coatings are designed and the efficiency of their performance; finally, successful applications (both current and potential) are de- scribed. The inherent designing flexibility of thermal-sprayed functional and smart coatings has been exploited to explore exciting new possibilities in many different fields. Some ap- plications include prevention of bacteria contamination and infection in hygienic environments (Fig. 3). A COMPREHENSIVE REVIEW OF CORROSION RESISTANCE OF THERMALLY-SPRAYED AND THERMALLY-DIFFUSED PROTECTIVE COATINGS ON STEEL STRUCTURES Sahar A. Galedari, Amirhossein Mahdavi, Fardad Azarmi, Ying Huang, and André McDonald Protective coatings arewidely used to promote corrosion resistance on the surfaces of steel components that are used in various industrial applications. Different surface engineering methods such as thermal spraying and thermal diffusion tech- niques canbeused to fabricate theseprotectivecoatings. Ther- mal sprayingprocesses have received significant attentiondue to their ability to deposit a variety of materials. Several metals such as zinc, aluminum, nickel, and chromium-based materi- als and their alloys can be deposited using thermal spraying processes to enhance the corrosion resistance and prolong the service life of steel components. On the other hand, technolo- gies based on thermal diffusion techniques are emerging due to their unique deposition features, which alleviate issues of cracking and delamination typical of thermal-sprayed coat- ings. In addition, their ability to protect inaccessible and com- plex components such as the inner surface of long tubing and pipelines is valuable. This work is a comprehensive review on short and long-term corrosion resistance of the most effective Fig. 3 — Three different examples of luminescence rare earth-doped layers (striped sections) on thermal barrier sensor coatings for (a) temperature measurement at the surface; (b) temperature measure within the TBC; and (c) dual temperature measurement, allowing for heat flux calculations. (a) (b) (c)