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Finally, this article briefly describes performance profiles
required to fulfill biological functions of osseoconductive bio-
ceramic coatings designed to improve osseointegration of hip
endoprostheses and dental root implants.
PHYSICOCHEMICAL CHARACTERISTICS OF
DUST PARTICLES IN HVOF SPRAYING AND
OCCUPATIONAL HAZARDS: CASE STUDY
IN A CHINESE COMPANY
Haihong Huang, Haijun Li, and Xinyu Li
Dust particles generated during thermal spray pose a
serious health risk to operators. Particles generated in the
high velocity oxy-fuel (HVOF) spray of WC-Co coatings were
Fig. 4. —
Schematic of cell-implant interaction mediated by a thin
calciumphosphate coating layer. A local decrease of pH results in
partial dissolution of the coatings, triggering the release of chemo-
taxia frombone. Addition of Ca
2+
and PO
4
3-
ions increases supersat-
uration of the extracellular fluid (ECF) with respect to hydroxylap-
atite, precipitating bone-like apatite and promoting subsequent
incorporation of osseoinductive proteins such as osteocalcin and
osteonectin as well as annexins and integrins.
characterized in terms of mass concentrations, particle size
distribution, micro morphologies, and composition. Results
show that the highest instantaneous exposure concentration
of dust particles is 140 mg/m
3
and the time weighted average
concentration is 34.2 mg/m
3
, which are approximately eight
and four times higher than the occupational exposure limits in
China, respectively. Large dust particles bigger than 10
μ
m in
size present a unique polygonal morphology or irregular block
of crushed powder, and smaller dust particles mainly exist in
the form of irregular or flocculent agglomerates. Some heavy
metals, such as chromium, cobalt, and nickel, are also present
inworkshop air with concentrations that exceed exposure lim-
its. Potential occupational hazards are further analyzed based
on dust particle characteristics. Exposure to the nanoparticles
is assessed using a control banding tool.
Fig. 5. —
Workshop schematic.