Influence of discharge power level on the properties of hydroxyapatite films deposited on Ti6A14V with RF magnetron sputtering

Abstract

The effects of discharge radio frequency (RF) power and film thickness were studied on the characteristics of Ca5(P04)30 H (hydroxyapatite) thin films fabricated by RF magnetron sputtering. The structure and chemical compo sition were investigated with a-step (thickness), scanning electron microscopy (SEM), X-ray diffraction (XRD), Ruth erford backscattering spectrometry (RBS), and infrared ab sorption spectrometry (FTIR). The films were analyzed assputtered and after annealing at 550°C under argon flow. SEM showed that the film surfaces had no cracks or other defects. X-ray diffraction showed that the deposited films were amorphous with low-discharge RF power, and crystalline with high-discharge RF power. After annealing, all the films had the same crystalline structure as apatite. However, the RBS measurements revealed that all films had a higher calcium-phosphate ratio than standard syn thetic hydroxyapatite. Furthermore, statistical testing of the RBS data revealed the existence of only a weak correlation between the Ca/P ratio and the discharge power level* Al though all sputtered films showed phosphate bonds in the infrared spectrum, only after annealing did the O H bonds of hydroxyapatite become visible.

Initial interfacial healing events around calcium phosphate (Ca‐P) coated oral implants

“…The final sur face roughness of these FA-HA coatings was Ra = 9.59 |im. Further, of the implants with a diameter of 4.0 mm, 18 were left uncoated (cpTi) and 18 were provided with an amorphous Ca-P (Ca-P-a) coating using a radiofrequency (rf) magnetron sputter process (van Dijk et al 1995a(van Dijk et al , 1995bWolke et al 1994). These implants were not gritblasted, but were argon-etched before sputter coat ing.…”

Crystallographic texture in pulsed laser deposited hydroxyapatite bioceramic coatings

“…Despite the fact that crystallographic texture is one of the dominant features that determine the properties of polycrystalline ceramics and is commonly observed in naturally occurring HA, its impact on the mechanical properties and bioactivity of HA-coated implants has so far received very little attention. Most of the references to preferred orientation of HA coatings in the literature are of serendipitous occurrences of texturing in coatings produced by various deposition techniques [28][29][30][31]. Efforts aimed at systematic studies and deliberate control of these orientation effects have been limited.…”

Surface Engineering for Bone Implants: A Trend from Passive to Active Surfaces

“…As a consequence, upon impingement of feedstock powders particles onto the implant surface, an adherent coating is formed due to partial or complete melting of the powder particles. Another physical technique that is often used to deposit strongly adherent HA onto implants is Radio Frequency (RF) magnetron sputtering ( Figure 2) [180][181][182][183][184]. Sputtering is a process whereby atoms or molecules of some materials are ejected in a vacuum chamber, becoming precursors for coating, due to bombardment with high-energy ions [31,185].…”