Samsiah Ahmad

Effect of soaking time on paste carburizing of carburized low carbon steel

Increase of soaking time contributed to the effectiveness of case depth formation, hardness properties and carbon content of carburized steel. This paper investigates the effect of different soaking time (7-9 hours) using powder and paste compound to the carburized steel. Low carbon steels were carburized using powder and paste compound for 7, 8 and 9 hours at temperature 1000°C. The transformation of microstructure and formation carbon rich layer was observed under microscope. The microhardness profiles were analyzed to investigate the length of case depth produced after the carburizing process. The increment of carbon content was considered to find the correlation between types of carburizing compound with time. Results shows that the longer carburized steel was soaked, the higher potential in formation of carbon rich layer, case depth and carbon content, which led to better hardness properties for carburized low carbon steel. Longer soaking time, 9 hours has a higher dispersion of carbon up to 41%-51% compare to 8 hours and 7 hours. By using paste carburizing, it has more potential of carbon atom to merge the microstructure to transform into cementite (1.53 wt% C) compare to powder (0.97 wt% C), which increases the hardness of carburized steel (13% higher).

Study On The Effect Of Corrosion Behaviour Of Stainless Steel Before And After Carburizing Heat Treatment

This study investigates the effect of corrosion behaviour of stainless steel before and after carburizing process. All samples were prepared based on the testing specification requirement and the chemical compositions of the stainless steel were obtained using spectrometer tester. Samples were then undergoing pack carburizing process by adding 50g of carbon powder as the carburizing agent. Then the samples were heated at 900 °C and 950 °C for 8 hours. To obtain corrosion rate, weight loss test was conducted and the samples were immersed in three different solutions which were distilled water, hydrochloric acid and sodium chloride. Hardness and density test were employed to measure the physical properties of the ASTM 304 stainless steel. The microstructures of all samples were observed using Olympus BX41M optical microscope. The resulting phases after each heat treatment were tested by x-ray diffraction (XRD) tester. The percentage of corrosion values, determined from this technique, showed fairly good agreement. Carburizing process produced a carburizing layer improved mechanical properties and corrosion resistance abilities

Effect Of Temperature Variation On Wear Behaviour Of Austenitic Stainless Steel

The effects of boronizing temperatures on the wear and hardness properties of austenitic stainless steel were investigated in this study. The samples were prepared in accordance to standard samples preparation for wear and hardness test. Pack boronizing were conducted using EKabor®1 powder medium at two different temperatures which are 850°C and 950°C. The wear resistance properties were evaluated though pin on disk test and the surface characterization was analyzed through scanning electron microscopy (SEM), observation. Vickers microhardness tester was performed to obtain the hardness of the samples. The results indicated that there are presences of FeB and Fe2B phases on both samples, but thicker FeB phase was produced at Po-950 samples. This resulted in reduction of abrasion wear properties but major improvement of the hardness properties of boronized stainless steel.

Enhancement of Stainless Steel's Mechanical Properties via Carburizing Process

Carburizing process is a method to disperse carbon into the steel surface in order to enhance its mechanical properties such as hardness and wear resistance. This paper study investigates the effect of carburizing temperature to the carbon dispersion layer in stainless steel. The standard AISI 304 stainless steel was carburized in two different temperatures which were 900°C and 950°C. The effect of carbon dispersion layers were observed and the results indicated that the increasing value of the average dispersion layer from 1.30 mm to 2.74 mm thickness was found to be related to increment of carburizing holding temperature . The increment of carbon thickness layer also resulted in improvement of hardness and tensile strength of carburized stainless steel.

ZnO/SnO2 nanoflower based ZnO template synthesized by thermal chemical vapor deposition

The ZnO/SnO2 nanoflower like structures was grown on a glass substrate deposited with seed layer using thermal chemical vapor deposition (CVD) with combining two source materials. The ZnO/SnO2 nanoflower like structures had diameter in the range 70 to 100nm. The atomic percentage of ZnO nanoparticle , SnO2 nanorods and ZnO/SnO2 nanoflower was taken using EDS. Based on the FESEM observations, the growth mechanism is applied to describe the growth for the synthesized nanostructures.

Proposed network forensic framework for analyzing IaaS cloud computing environment

Cloud computing technology offers new way in providing computing resources and applications on demand but it is explicitly prone to the cybercrime. Therefore, it is challenged forensic investigators to conduct investigation in Infrastructure as a Service (IaaS) Cloud using traditional framework. This is exacerbated with the limitations of collecting forensic data from different geographical locations and environment in IaaS Cloud. Thus, in this paper proposes a network forensic framework that can be tailored in forensic analysis in IaaS Cloud Computing environment. The proposed framework is tailored with the existing frameworks with Digital Forensic Model (DFM) in which each phase is elucidated. The proposed framework is then tested and evaluated through experimental using virtualisation environment. The results shows that the proposed framework can be pragmatic implement in IaaS Cloud which contribute in developing of a forensic tool and guidelines for forensic investigator conducting investigation IaaS Cloud as future works.

Effect of RF Power on the Structural Properties of Magnetron Sputtered ZnO Thin Films Deposited at Room Temperature

Zinc oxide thin films were prepared at room temperature in pure argon ambient on glass substrates by RF magnetron sputtering. The effect of sputtering power (50~250 Watt) on the structural properties of the film were investigated. The thickness of ZnO thin films was measured using surface profiler (Dektak 150+). Atomic force microscopy machine (AFM-Park system XE-100) was used to characterize the morphology while the crystalinity have been characterized using XRD (Rigaku Ultima IV). It was found that the thickness, growth rate and RMS roughness increases with increasing RF power. All films exhibit the (002) plane which correspond to hexagonal wurtzite structure with the highest peak at 150 Watt.

Sensitivity of ZnO Based NH3 Sensor by RF Magnetron Sputtering

Zinc Oxide (ZnO) thin films were deposited onto SiO2/Si substrates using radio frequency (RF) magnetron sputtering method as an Ammonia (NH3) sensor. The dependence of RF power (50~300 Watt) on the structural properties and sensitivity of NH3 sensor were investigated. XRD analysis shows that regardless of the RF power, all samples display the preferred orientation on the (002) plane. The results show that the ZnO deposited at 200 Watt display the highest sensitivity value which is 44%.

Influence of Post Annealing Temperature on the Properties of ZnO Films Prepared by RF Magnetron Sputtering

Zinc Oxide (ZnO) films were prepared on unheated glass substrate by radio frequency (RF) magnetron sputtering technique and post deposition annealing of the ZnO thin film were performed at 350, 400, 450 and 500°C. Post annealing temperature was found to improve the structural and electrical characteristics of the deposited films. The structural properties of the films were carried out by the surface profiler, X-Ray diffraction (XRD), atomic force microscopy (AFM) and field emission scanning electron microscope (FESEM) while the electrical properties were measured using current voltage (I-V) probe measurement system. All samples exhibit the (002) peak and the sample annealed at 500°C gives the highest crystalline quality, highest Rms roughness (1.819 nm) and highest electrical conductivity (3.28 x 10-3 Sm-1).