300
Y. Sasikumar et al.
1.3.1 Plasma Spraying
The plasma spraying method is employed to create nano-engineered surfaces having
a dimension of less than 100 nm. The process includes the deposition of various
charged metallic ions using a vacuum or through plasma guided kinetic energy over
the implant material surface. Different types of coating materials such as Ti, Ag, Au
were coated on metals, polymers, and ceramics. This method is generally adopted,
and its main usage was the deposition of hydroxyapatite (HA) or calcium phosphate
coatings to accelerate the bone integration process during service, which is essential
for the implant materials. Hydroxyapatite coated implants were employed and led to
a high percentage of bone-implant contact. This method also has several limitations,
such as variations in the coating composition, lack of long-term adherence, and the
non-uniform thickness of the deposited layer over the substrate materials, resulting
in health hazards [6].
1.3.2 Sputtering
Sputtering is a common process in which a thin film of the ceramic layer is deposited
from the ejected molecules or atoms due to the bombardment of high energy ions.
This method is commonly used to achieve higher adhesion between the coating and
substrate. Surface properties such as corrosion, wear resistance, biocompatibility can
be effectively improved using this method. Nevertheless, the main drawback of this
technique is a slow process with a lower deposition rate. The slow deposition rate
can be improved using magnetron and radiofrequency sputtering [6].
• Magnetron sputtering:
Magnetron sputtering is mainly carried out to deposit the viable thin film coating.
This method can preserve the mechanical properties of a material, and also maintain its bioactivity. The magnetron sputtering process can be carried out at ambient
temperature as well as at various temperatures. Further, the sputtering chambers can
be designed based on the experimental condition for the coating deposition [6].
• Radiofrequency sputtering:
Radiofrequency sputtering is generally used for thin-film calcium phosphate
coating deposition over the surface of implants. The advantage of this method was the
superior adhesion compared with other coating methods. This was mainly due to the
deposition of material with high energy penetrating to the surface of the substrates.
However, the main disadvantage in this method i.e., the crystalline nature of the
coating surface, strong adhesion to the coating surface, and the alteration of CaP
ratio easily.
Y. Sasikumar et al.
1.3.1 Plasma Spraying
The plasma spraying method is employed to create nano-engineered surfaces having
a dimension of less than 100 nm. The process includes the deposition of various
charged metallic ions using a vacuum or through plasma guided kinetic energy over
the implant material surface. Different types of coating materials such as Ti, Ag, Au
were coated on metals, polymers, and ceramics. This method is generally adopted,
and its main usage was the deposition of hydroxyapatite (HA) or calcium phosphate
coatings to accelerate the bone integration process during service, which is essential
for the implant materials. Hydroxyapatite coated implants were employed and led to
a high percentage of bone-implant contact. This method also has several limitations,
such as variations in the coating composition, lack of long-term adherence, and the
non-uniform thickness of the deposited layer over the substrate materials, resulting
in health hazards [6].
1.3.2 Sputtering
Sputtering is a common process in which a thin film of the ceramic layer is deposited
from the ejected molecules or atoms due to the bombardment of high energy ions.
This method is commonly used to achieve higher adhesion between the coating and
substrate. Surface properties such as corrosion, wear resistance, biocompatibility can
be effectively improved using this method. Nevertheless, the main drawback of this
technique is a slow process with a lower deposition rate. The slow deposition rate
can be improved using magnetron and radiofrequency sputtering [6].
• Magnetron sputtering:
Magnetron sputtering is mainly carried out to deposit the viable thin film coating.
This method can preserve the mechanical properties of a material, and also maintain its bioactivity. The magnetron sputtering process can be carried out at ambient
temperature as well as at various temperatures. Further, the sputtering chambers can
be designed based on the experimental condition for the coating deposition [6].
• Radiofrequency sputtering:
Radiofrequency sputtering is generally used for thin-film calcium phosphate
coating deposition over the surface of implants. The advantage of this method was the
superior adhesion compared with other coating methods. This was mainly due to the
deposition of material with high energy penetrating to the surface of the substrates.
However, the main disadvantage in this method i.e., the crystalline nature of the
coating surface, strong adhesion to the coating surface, and the alteration of CaP
ratio easily.