Influence of bath temperature and deposition time on hardness and magnetisation of electrodeposited Nickel Manganese Tungsten thin films
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-04-01 |
| Journal | Journal of Ovonic Research |
| Authors | P. Kirthika, N. Thangaraj, Periyasamy Anitha |
| Citations | 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis study investigates the structural, mechanical, and magnetic properties of electrodeposited Nickel Manganese Tungsten (Ni-Mn-W) thin films, focusing on optimization via bath temperature and deposition time for engineering applications.
- Optimal Processing Window: A bath temperature of 45 °C was identified as optimal, yielding films with the lowest microstrain, minimum dislocation density, and stoichiometric composition.
- Structural Quality: Films deposited at 45 °C achieved a maximum average crystallite size of approximately 30 nm, confirming the successful synthesis of nanoscale material.
- Enhanced Mechanical Performance: Vickers Hardness measurements showed that hardness increased significantly with bath temperature up to 45 °C, attributed to the reduction of grain size and internal strain.
- Magnetic Transition: The magnetic behavior is highly dependent on grain size; coercivity and saturation magnetization decreased as particle size increased, indicating a transition from multi-domain to single-domain/superparamagnetic states.
- Relevance for Cooling: The synthesized Ni-Mn-W nanoparticles exhibit enhanced magnetization and reduced hysteresis compared to their bulk counterparts, making them highly promising candidates for magnetic refrigeration technology.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Material System | Ni-Mn-W | Thin Film | Electrodeposited on Cu substrate |
| Optimal Bath Temperature | 45 | °C | Yields minimum microstrain, dislocation density, and stoichiometric composition |
| Current Density | 3 | mA/cm2 | Constant deposition parameter |
| Electrolyte pH | 4 to 5 | N/A | Maintained using concentrated H2SO4 |
| Maximum Average Crystallite Size | ~30 | nm | Achieved at 45 °C bath temperature |
| Minimum Dislocation Density (45 °C) | 1.1535 x 1015 | lin/m2 | Measured at 34.7431° 2 Theta peak |
| Maximum Vickers Hardness (25g load) | ~120 | VHN | Achieved at 45 °C bath temperature |
| Coercivity Range | 72.620 to 232.21 | Oe | Varies based on temperature and time (15-45 min) |
| Maximum Magnetization (45 °C, 45 min) | 2.5611 x 10-3 | emu | Highest measured value |
Key Methodologies
Section titled âKey MethodologiesâThe Ni-Mn-W thin films were prepared using a constant current density electrodeposition technique on a copper substrate.
- Electrode Preparation:
- Copper substrate (2 x 7 cm) served as the cathode. It was cleaned with 0.01N dilute sulfuric acid, acetone, and distilled water.
- Nickel plate served as the anode, cleaned with acetone and hot double distilled water.
- The cathode was masked to expose a deposition area of 2 x 5 cm.
- Electrolyte Composition:
- Aqueous solution containing: 0.1 M NiCl2.6H2O, 0.1 M MnCl2.H2O, and 0.05 M Na2WO4.
- Process Control:
- The pH value was maintained between 4 and 5 using concentrated H2SO4 acid.
- A constant current density of 3 mA/cm2 was applied via a power supply.
- Variable Parameters:
- Bath temperature was varied across three levels: 35 °C, 45 °C, and 55 °C.
- Deposition time was optimized at 15, 30, and 45 minutes.
- Characterization Techniques:
- Structural: X-ray Diffraction (XRD) for crystal structure and crystallite size (using Debye-Scherrer relation).
- Morphological: Scanning Electron Microscopy (SEM).
- Compositional: Energy Dispersive X-ray Spectroscopy (EDAX).
- Magnetic: Vibrating Sample Magnetometer (VSM) for coercivity and saturation magnetization.
- Mechanical: Vickers Hardness tester using a diamond indenter method (loads from 25 g to 300 g).
Commercial Applications
Section titled âCommercial ApplicationsâThe enhanced mechanical and magnetic properties of electrodeposited Ni-Mn-W thin films make them suitable for several high-performance engineering sectors:
- Magnetic Refrigeration Technology: The low hysteresis and enhanced magnetization observed in the Ni-Mn-W nanoparticles are critical for developing commercially viable, highly efficient solid-state magnetic cooling systems (Magnetocaloric Effect, MCE).
- Micro Electro Mechanical Systems (MEMS): The high strength, good ductility, and low internal stress of the Ni-Mn films are ideal for fabricating complex mechanical and magnetic components, including:
- Precision gears and motors.
- Flexure spring arms and latches.
- High-Density Data Storage: The controlled magnetic properties and nanoscale structure are applicable in the development of advanced high-density recording media.
- Magnetic Actuators and Transformers: The attractive magnetic properties resulting from the combination of ferromagnetic nickel and paramagnetic manganese are useful for high-performance transformer cores and magnetic actuators.
- Energy Storage Devices (Supercapacitors): While the study focuses on structural properties, the base materials (Ni and transition metal oxides) are commonly used as electrode materials in Electrochemical Supercapacitors (ESs) due to their high power density and excellent reversibility.
View Original Abstract
The Nickel Manganese Tungsten (Ni-Mn-W) thin films were prepared at different temperature and time of deposition on copper substrate. The crystal structure and morphology of deposits were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD revealed that the structure of Ni-Mn-W thin films with have an average grain size of about 28 nm for 45o C. The elemental analysis of Ni-Mn-W thin films were obtained by energy dispersive X-ray spectroscopy (EDAX). The magnetic properties of electrodeposited Ni-Mn-W thin films were obtained by vibrating sample magnetometer (VSM). The magnetic parameters of Ni-Mn-W films such as coercivity and saturation magnetization were decreased with increasing of grain size. The hardness of the films was studies by Vicker Hardness tester through diamond intender method.