Papers by Prof. Dr. S. Jawid Askari
Advanced Materials Research, 2011
Surface Engineering, 2009
Nanocrystalline diamond (NCD) films on titanium alloys are of importance for tribology and biomed... more Nanocrystalline diamond (NCD) films on titanium alloys are of importance for tribology and biomedical implants. However, due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in ...
Vacuum, Feb 1, 2008
The fabrication of a well-adherent diamond film on titanium and its alloys is always problematica... more The fabrication of a well-adherent diamond film on titanium and its alloys is always problematical due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving very high nucleation density. In this work, well-adherent and smooth nanocrystalline diamond (NCD) thin film is successfully deposited on pure titanium substrate by microwave plasma-assisted chemical vapor deposition (MWPCVD) method in Ar/CH 4 environment. It is found that the average grain size is less than 20 nm with a surface roughness value as low as 12 nm. Morphology, surface roughness, diamond crystal orientation and quality are obtained by characterizing the sample with field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy, respectively. Detailed experimental results and mechanisms for NCD film deposition are discussed. r
International Journal of Modern Physics B, 2009
In contrast to their exceptional mechanical properties, titanium and its alloys possess poor fric... more In contrast to their exceptional mechanical properties, titanium and its alloys possess poor friction and wear characteristics. Nanocrystalline diamond (NCD) films appear to be a promising solution for their tribological problem due to their smooth surfaces and small grain size. However, ...
Advanced Materials Research, 2011
Page 1. EXPERIMENTAL AND FEM STUDY OF SERRATED CHIP FORMATION IN HIGH SPEED TURNING PROCESSES U.U... more Page 1. EXPERIMENTAL AND FEM STUDY OF SERRATED CHIP FORMATION IN HIGH SPEED TURNING PROCESSES U.Umer¹, LJ Xie 2 , SJ Askari¹, SN Danish¹, SI Butt¹ 1. Institute of Manufacturing Engineering, Pakistan Navy Engg. ...
Mineral quartz is a hard / rigid crystalline stone accessible in large quantities all over the wo... more Mineral quartz is a hard / rigid crystalline stone accessible in large quantities all over the world in a variety
of shapes. This mineral is a common element on the soil of earth consisting of more than 26 % of the earth layer and is
usually originate at the earth’s surface with other elements mostly with oxygen thus commonly known as silicate /
silicon dioxide (SiO2). It is largely composed of silicon which is known to be an ideal semi-conductor of electricity
because in silicon electrons are relatively confined closely until some change in their environment causes them to flow
freely. This special / unique characteristic of silicon makes it the most suitable element in electronic and photovoltaic
industry where it is used in many applications depending upon its purity level with respect to silicon.
The world is blessed with large deposits of Quartz which are spread from USA to Brazil and India to
Afghanistan in many shapes and varieties. These varieties of shapes are being used in so many ways depending upon the
composition and elemental distribution. Similarly, Pakistan is also blessed with reasonable proven mineral quartz
deposits of around 175 million metric tons but unfortunately it is not being used as per its chemical composition /
potential. The reason may be due to the lack of awareness among local people that how much this mineral is important
viz-a-viz non-availability of proper extraction / conversion facilities require for the extraction of MGS from this mineral
quartz. Due to the lack of awareness and lack of extraction / conversion facilities in Pakistan, this mineral quartz is
being used as refractory bricks, in glass and ceramic industries and in different types of construction works, while a
major part of it is exported to other countries of the world.
The presence of more than 95 % of silicon dioxide in quartz of Pakistan certify establishment of extraction /
conversion facility in the country which lead to the extraction of MGS never been done so far in the country. If MGS
with silicon purity level of around 96% is achieved through this extraction process, further purification processes can be
applied which is a step towards achieving Electronic Grade Silicon and Solar Grade Silicon. This will open a new era of
advancement in the field of electronic and photovoltaic industry in Pakistan thus strengthening the economy of the
developed country like Pakistan
Vacuum, 2008
The fabrication of a well-adherent diamond film on titanium and its alloys is always problematica... more The fabrication of a well-adherent diamond film on titanium and its alloys is always problematical due to the different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving very high nucleation density. In this work, well-adherent and smooth nanocrystalline diamond (NCD) thin film is successfully deposited on pure titanium substrate by microwave plasma-assisted chemical vapor deposition (MWPCVD) method in Ar/CH 4 environment. It is found that the average grain size is less than 20 nm with a surface roughness value as low as 12 nm. Morphology, surface roughness, diamond crystal orientation and quality are obtained by characterizing the sample with field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy, respectively. Detailed experimental results and mechanisms for NCD film deposition are discussed. r
Surface Engineering, 2007
Diamond coatings on pure titanium substrates are of interest for tribological and biomedical impl... more Diamond coatings on pure titanium substrates are of interest for tribological and biomedical implants; however, due to different thermal expansion coefficients of the two materials, the complex nature of the interlayer formed during diamond deposition, and the difficulty in achieving ...
Surface and Coatings Technology, 2007
To enhance the mechanical properties of TiN coating on magnesium alloy, metal vapor vacuum arc (M... more To enhance the mechanical properties of TiN coating on magnesium alloy, metal vapor vacuum arc (MEVVA) ion implantation was performed to modify magnesium alloy substrate before TiN film deposition. Implantation energy was fixed at 45 keV and dose was at 9 × 10 17 cm − 2 . TiN coatings were deposited by magnetically filtered vacuum-arc plasma source on unimplanted and implanted substrate. The microstructure composition distribution and phase structure were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The chemical states of some typical elements of the TiN coating were analyzed by means of X-ray photoelectron spectroscopy (XPS). The properties of corrosion resistance of TiN coatings were studied by CS300P electrochemical-corrosion workstation, and the mechanism of the corrosion resistance was also discussed.
Materials Science and Engineering: A, 2008
This paper describes the sintering of a martensitic stainless steel alloy with addition of Si 3 N... more This paper describes the sintering of a martensitic stainless steel alloy with addition of Si 3 N 4 . Sintering behavior was studied at different sintering temperatures ranging from 1250 to 1400 °C with different holding times (2080 min) and with varying Si 3 N 4 . Results showed ...
Journal of University of Science and Technology Beijing, Mineral, Metallurgy, Material, 2007
TiC based cermets were produced with FeCr, as a binder, by conventional P/M (powder metallurgy) t... more TiC based cermets were produced with FeCr, as a binder, by conventional P/M (powder metallurgy) to near >97% of the theoretical density. Sintering temperature significantly affects the mechanical properties of the composite. The sintering temperature of >1360°C ...
Journal of University of Science and Technology Beijing, Mineral, Metallurgy, Material, 2006
Nanocrystalline diamond (NCD) film deposition on pure titanium and Ti alloys is extraordinarily d... more Nanocrystalline diamond (NCD) film deposition on pure titanium and Ti alloys is extraordinarily difficult because of the high diffusion coefficient of carbon in Ti, the large mismatch in their thermal expansion coefficients, the complex nature of the interlayer formed during diamond ...
High temperature furnaces are the most suitable furnaces with the capabilities necessary to proce... more High temperature furnaces are the most suitable furnaces with the capabilities necessary to proceed
further in the research area of obtaining cheap and high quality Metallurgical Grade Silicon (MGS). The
Silicon Dioxide (SiO2) / Silicate generally known as quartz is a hard crystalline mineral stone abundantly
available in large quantities all over the world in a variety of appearances comprising about 26 % of the earth
layer with other elements (mostly oxygen). In Pakistan this mineral is available excessively in Jhangshahi,
Sindh and other parts of the country, but is not being used in extracting MGS due to non-availability of high
temperature specialized furnaces. However this mineral is used in construction industries and in different steel
manufacturing industries as slag. The element silicon which is a known semiconductor (in which electrons are
relatively tightly bound until some change in their environment causes them to flow freely) can be obtained
through a series of purification processes of MGS (which can be extracted from this mineral quartz through
specially designed low scale, high temperature hybrid furnace). The melting of quartz requires a temperature of
around 2000
O
C, with a control environment to obtained MGS with a suitable silicon purity level of around 90 –
95%. During this research work a hybrid furnace with low scale is designed and developed that can attained
temperature range of around 2000
O
C in order to achieve proper and thorough melting of specially prepared raw
mineral quartz. The capacity of this furnace is anticipated to be 3-4 Kg of charge initially, which can be further
enhanced with both gas as well as electrical firing option. The tests showed that a time of 60-90 minutes is
required to heat up the furnace completely in order to attain the required temperature. The time required to melt
the first charge of 1 kg was approximately 2 hours at the melting rate of 8.30 gram / minute with average
electrode consumption of 0.0467cm / minute (when fired electrically) while average gas consumption of 90 ccf
(when fired with gas option). The average MGS production during this research work is anticipated to be 300
grams approximately from 1 kg of raw mineral quartz.
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Papers by Prof. Dr. S. Jawid Askari
of shapes. This mineral is a common element on the soil of earth consisting of more than 26 % of the earth layer and is
usually originate at the earth’s surface with other elements mostly with oxygen thus commonly known as silicate /
silicon dioxide (SiO2). It is largely composed of silicon which is known to be an ideal semi-conductor of electricity
because in silicon electrons are relatively confined closely until some change in their environment causes them to flow
freely. This special / unique characteristic of silicon makes it the most suitable element in electronic and photovoltaic
industry where it is used in many applications depending upon its purity level with respect to silicon.
The world is blessed with large deposits of Quartz which are spread from USA to Brazil and India to
Afghanistan in many shapes and varieties. These varieties of shapes are being used in so many ways depending upon the
composition and elemental distribution. Similarly, Pakistan is also blessed with reasonable proven mineral quartz
deposits of around 175 million metric tons but unfortunately it is not being used as per its chemical composition /
potential. The reason may be due to the lack of awareness among local people that how much this mineral is important
viz-a-viz non-availability of proper extraction / conversion facilities require for the extraction of MGS from this mineral
quartz. Due to the lack of awareness and lack of extraction / conversion facilities in Pakistan, this mineral quartz is
being used as refractory bricks, in glass and ceramic industries and in different types of construction works, while a
major part of it is exported to other countries of the world.
The presence of more than 95 % of silicon dioxide in quartz of Pakistan certify establishment of extraction /
conversion facility in the country which lead to the extraction of MGS never been done so far in the country. If MGS
with silicon purity level of around 96% is achieved through this extraction process, further purification processes can be
applied which is a step towards achieving Electronic Grade Silicon and Solar Grade Silicon. This will open a new era of
advancement in the field of electronic and photovoltaic industry in Pakistan thus strengthening the economy of the
developed country like Pakistan
further in the research area of obtaining cheap and high quality Metallurgical Grade Silicon (MGS). The
Silicon Dioxide (SiO2) / Silicate generally known as quartz is a hard crystalline mineral stone abundantly
available in large quantities all over the world in a variety of appearances comprising about 26 % of the earth
layer with other elements (mostly oxygen). In Pakistan this mineral is available excessively in Jhangshahi,
Sindh and other parts of the country, but is not being used in extracting MGS due to non-availability of high
temperature specialized furnaces. However this mineral is used in construction industries and in different steel
manufacturing industries as slag. The element silicon which is a known semiconductor (in which electrons are
relatively tightly bound until some change in their environment causes them to flow freely) can be obtained
through a series of purification processes of MGS (which can be extracted from this mineral quartz through
specially designed low scale, high temperature hybrid furnace). The melting of quartz requires a temperature of
around 2000
O
C, with a control environment to obtained MGS with a suitable silicon purity level of around 90 –
95%. During this research work a hybrid furnace with low scale is designed and developed that can attained
temperature range of around 2000
O
C in order to achieve proper and thorough melting of specially prepared raw
mineral quartz. The capacity of this furnace is anticipated to be 3-4 Kg of charge initially, which can be further
enhanced with both gas as well as electrical firing option. The tests showed that a time of 60-90 minutes is
required to heat up the furnace completely in order to attain the required temperature. The time required to melt
the first charge of 1 kg was approximately 2 hours at the melting rate of 8.30 gram / minute with average
electrode consumption of 0.0467cm / minute (when fired electrically) while average gas consumption of 90 ccf
(when fired with gas option). The average MGS production during this research work is anticipated to be 300
grams approximately from 1 kg of raw mineral quartz.
of shapes. This mineral is a common element on the soil of earth consisting of more than 26 % of the earth layer and is
usually originate at the earth’s surface with other elements mostly with oxygen thus commonly known as silicate /
silicon dioxide (SiO2). It is largely composed of silicon which is known to be an ideal semi-conductor of electricity
because in silicon electrons are relatively confined closely until some change in their environment causes them to flow
freely. This special / unique characteristic of silicon makes it the most suitable element in electronic and photovoltaic
industry where it is used in many applications depending upon its purity level with respect to silicon.
The world is blessed with large deposits of Quartz which are spread from USA to Brazil and India to
Afghanistan in many shapes and varieties. These varieties of shapes are being used in so many ways depending upon the
composition and elemental distribution. Similarly, Pakistan is also blessed with reasonable proven mineral quartz
deposits of around 175 million metric tons but unfortunately it is not being used as per its chemical composition /
potential. The reason may be due to the lack of awareness among local people that how much this mineral is important
viz-a-viz non-availability of proper extraction / conversion facilities require for the extraction of MGS from this mineral
quartz. Due to the lack of awareness and lack of extraction / conversion facilities in Pakistan, this mineral quartz is
being used as refractory bricks, in glass and ceramic industries and in different types of construction works, while a
major part of it is exported to other countries of the world.
The presence of more than 95 % of silicon dioxide in quartz of Pakistan certify establishment of extraction /
conversion facility in the country which lead to the extraction of MGS never been done so far in the country. If MGS
with silicon purity level of around 96% is achieved through this extraction process, further purification processes can be
applied which is a step towards achieving Electronic Grade Silicon and Solar Grade Silicon. This will open a new era of
advancement in the field of electronic and photovoltaic industry in Pakistan thus strengthening the economy of the
developed country like Pakistan
further in the research area of obtaining cheap and high quality Metallurgical Grade Silicon (MGS). The
Silicon Dioxide (SiO2) / Silicate generally known as quartz is a hard crystalline mineral stone abundantly
available in large quantities all over the world in a variety of appearances comprising about 26 % of the earth
layer with other elements (mostly oxygen). In Pakistan this mineral is available excessively in Jhangshahi,
Sindh and other parts of the country, but is not being used in extracting MGS due to non-availability of high
temperature specialized furnaces. However this mineral is used in construction industries and in different steel
manufacturing industries as slag. The element silicon which is a known semiconductor (in which electrons are
relatively tightly bound until some change in their environment causes them to flow freely) can be obtained
through a series of purification processes of MGS (which can be extracted from this mineral quartz through
specially designed low scale, high temperature hybrid furnace). The melting of quartz requires a temperature of
around 2000
O
C, with a control environment to obtained MGS with a suitable silicon purity level of around 90 –
95%. During this research work a hybrid furnace with low scale is designed and developed that can attained
temperature range of around 2000
O
C in order to achieve proper and thorough melting of specially prepared raw
mineral quartz. The capacity of this furnace is anticipated to be 3-4 Kg of charge initially, which can be further
enhanced with both gas as well as electrical firing option. The tests showed that a time of 60-90 minutes is
required to heat up the furnace completely in order to attain the required temperature. The time required to melt
the first charge of 1 kg was approximately 2 hours at the melting rate of 8.30 gram / minute with average
electrode consumption of 0.0467cm / minute (when fired electrically) while average gas consumption of 90 ccf
(when fired with gas option). The average MGS production during this research work is anticipated to be 300
grams approximately from 1 kg of raw mineral quartz.