Deposition Methods for Microstructured and Nanostructured Coatings on Metallic Bone Implants: A Review

Table 1

A summary of a selection of characteristics of thermal spray processes.

Characteristic	Cold spray	Combustion		Plasma
		HVOF	D-Gun	Nontransferred arc	RF inductive	Transferred arc
Gas temperature; (K)	>300	3000–3300	≥4000	12,000–14,000	8,000–10,000	12,000–14,000
Substrate temperature; (K)	>300	350–450	350–450	350–400	350–400	Fuses base metal
Particle velocity (m/s)	≤900	≤700	≤3000	≤560	15–20	490
Bond strength (MPa)	≤50	>80	>70	14–69	≤35	>200
Coating thickness; (mm)	0.01–0.05	0.05–5.0	0.05–5.0	0.05–5.0	0.05–5.0	0.5–6.0
Porosity; (%)	1–5	<2	<2	1–5	1–5	<2

Data on characteristics taken from references [39–41].
Particle velocity must be above the critical velocity for specified coating material.
Without the use of additional cooling system.