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Sintering peculiarities for hydroxyapatite with different degrees of crystallinity
Z Zyman1, I Ivanov, D Rochmistrov
1Physics of Solids Department, Physics Faculty, Kharkiv V.N.Karazin National University, 4 Svoboda Squ., Kharkiv 61077, Ukraine.
Journal of Biomedical Materials Research
|November 28, 2000
Summary
Hydroxyapatite powder
Area of Science:
- Materials Science
- Ceramics Engineering
- Biomaterials
Background:
- Sintering temperature reduction is key for hydroxyapatite processing.
- Powder characteristics, specifically crystalline and amorphous-like constituents, influence sintering behavior.
Purpose of the Study:
- To investigate the relationship between powder constituents and hydroxyapatite sintering mechanisms.
- To analyze the impact of crystallinity on shrinkage behavior and sintering temperatures.
Main Methods:
- Analysis of hydroxyapatite powder with varying crystalline and amorphous-like constituents.
- Observation of pressings' shrinkage curves during heating from 600-700°C up to 900°C.
- Identification of sintering mechanisms: particle sliding and diffusion.
Main Results:
- Shrinkage initiates at 600-700°C via particle sliding, influenced by gas exuded from amorphous-like constituent crystallization.
- Higher crystallinity leads to higher sintering temperatures and smoothed shrinkage curves.
- Fully crystalline powders exhibit minimal sliding, with significant shrinkage only above 900°C due to diffusion.
Conclusions:
- The degree of crystallinity in hydroxyapatite powder dictates the dominant sintering mechanism and temperature.
- Controlling the crystalline-amorphous ratio allows for tailored sintering processes and reduced processing temperatures.