Biomedical subjects

H C Gledhill

Publications and source records attributed to H C Gledhill.

3 recordsLinked to original sources

PubMed2001

In vitro dissolution behaviour of two morphologically different thermally sprayed hydroxyapatite coatings.

Two types of hydroxyapatite coating on titanium substrates were produced by vacuum plasma spraying and detonation gun spraying. The response of the coatings to immersion in Ringer's solution at pH 7.2 and held at 37 degrees C for periods of one, two, four and eight weeks was compared. X-ray diffraction was used to measure changes in crystallinity and residual stresses. Porosity and coating thickness were measured using optical microscopy combined with image analysis. Surface morphology was characterised using scanning electron microscopy and Talysurf measurements. The DGUN coatings were found initially to have a lower crystallinity and porosity but higher surface roughness and residual stress level than the VPS coatings. This resulted in a higher rate of dissolution compared to the more stable VPS coatings.

Biocompatible Materials↗

PubMed2001

In vitro fatigue behaviour of vacuum plasma and detonation gun sprayed hydroxyapatite coatings.

The fatigue behaviour of vacuum plasma sprayed (VPS) and detonation gun sprayed (DGUN) hydroxyapatite coatings on titanium substrates has been compared in air and in buffered Ringer's solution. There was an increase in the surface microcracking and bulk porosity of both types of coating tested in air. After 1 million cycles in Ringer's solution the VPS coatings had completely delaminated from their substrates. In contrast the DGUN coatings retained their integrity when tested up to 10 million cycles but were beginning to show signs of delamination at the interface.

Durapatite↗

PubMed1999

Direct morphological comparison of vacuum plasma sprayed and detonation gun sprayed hydroxyapatite coatings for orthopaedic applications.

Hydroxyapatite coatings on titanium substrates were produced using two thermal spray techniques vacuum plasma spraying and detonation gun spraying. X-ray diffraction was used to compare crystallinity and residual stresses in the coatings. Porosity was measured using optical microscopy in conjunction with an image analysis system. Scanning electron microscopy and surface roughness measurements were used to characterise the surface morphologies of the coatings. The vacuum plasma sprayed coatings were found to have a lower residual stress, a higher crystallinity and a higher level of porosity than the detonation gun coatings. It is concluded that consideration needs to be given to the significance of such variations within the clinical context.

Aerosols↗