In the field of non-silicon MEMSs (micro-electro-mechanical systems), nickel, with its mature preparation method, good compatibility with non-silicon MEMS processes, and excellent mechanical properties, is one of the commonly used structural materials. By effectively combining it with non-silicon MEMS processes, nickel is widely used in typical process systems such as LIGA (Lithography, Galvanoformung, Abformung)/UV-LIGA (Ultraviolet Lithography, Galvanoformung, Abformung). However, with the rapid development of the non-silicon MEMS field, pure nickel materials are no longer able to meet current material demands. Alternatively, nickel–cobalt composite materials have excellent mechanical properties, thermal stability, corrosion resistance, and good adaptability to processing technology because cobalt has unique advantages as a reinforcing phase, including excellent wear resistance, corrosion resistance, and high hardness. This article examines the current methods for preparing nickel–cobalt alloys by focusing on composite electrodeposition of coatings and analyzing their advantages and disadvantages. Based on this, the effect of the composite electrodeposition conditions on the formation mechanism of nickel–cobalt alloy coatings is discussed. Then, the research status of composite electrodeposition methods mainly based on nickel–cobalt nanocomposites is discussed. Finally, a new direction for future work on nickel–cobalt composite materials mainly composed of nickel–cobalt nanomaterials prepared by composite electrodeposition is proposed, and its application prospects in non-silicon MEMS fields are discussed.

In recent decades, with the advancement of micro-electro-mechanical systems technology, traditional materials have become insufficient to meet the demands of cutting-edge technology for various material properties. Composites have attracted widespread attention as an effective and viable solution. Silicon carbide whiskers (SiCw) have emerged as excellent reinforcements due to their high thermal conductivity, low thermal expansion coefficient, high melting point, superior mechanical properties, and high chemical stability. This article provides a comprehensive review of the reinforcement mechanisms and current research state of SiCw-reinforced composites. The reinforcement mechanisms include mainly grain refinement, load transfer, and crack bridging. The composites are categorized based on the type of the matrix: ceramic-based, metal-based, and polymer-based composites. The influence and parameter performance of the reinforcement mechanism on SiCw-reinforced composite materials with different matrices vary. However, the key to improving SiCw-reinforced composites lies in understanding the interplay of properties between the matrix and the reinforcement, as well as the ordered and regular distribution and binding at the interface. Finally, the current state and limitations of SiCw-reinforced composites are summarized, and future development trends are discussed. This article represents a great contribution to the future applications of SiCw-reinforced composite materials.

The microspring is a typical type of device in MEMS devices, with a wide range of application scenarios and demands, among which a popular one is the microelectroformed nickel-based planar microspring prepared by the UV-LIGA technology based on the SU-8 adhesive. It is worth noting that the yield strength of the electrodeposited nickel microstructure is low, and the toughness of the structure is not high, which is unbeneficial for the enduring and stable operation of the spring. The paper mainly presents the methods of preparing high-aspect-ratio Ni/SiCw microstructures for MEMS devices based on UV-LIGA technology, developing Ni/SiCw-based microspring samples with a thickness of 300 μm, and applying a DMA tensile tester for mechanical property tests and characterization. In addition, the paper explores the influence of heat treatment at 300 °C and 600 °C on the tensile properties and microstructure of composite coatings. The results show that the W-form microspring prepared from Ni/SiCw composites not only has a wider linear range (about 1.2 times wider) than that of pure nickel material but also has a stronger resistance capacity to plastic deformation, which is competent for MEMS device applications in environments below 300 °C. The research provides a frame of reference and guidance for improving the stable cyclic operating life of such flat springs.

Contactless tuning of signals represents a promising avenue for advancing topological phononics and photonics devices, particularly in the frequency and spatial domains. For topological phase transitions, breaking the spatial inversion symmetry geometrically to obtain an open topological band gap is a typical way to introduce perturbations. This approach has great limitations in achieving reconfigurable topological protection routes. We present a thermally modulated two-dimensional elastic topological insulator made from a patterned substrate and a temperature-sensitive vanadium dioxide film, allowing elastic waves to propagate in the suspended region of the 2D material. The topological phase transition is activated by locally heating a portion of the unit cell. This heating induces a phase transition in the material by exploiting changes in mechanical properties, achieving symmetry breaking. The topological valley-locked states with strong localization at the interface are obtained by placing unit cells with different chirality adjacent to each other at the omnidirectional bulk band gap. Full-field simulations confirm both the reconfigurability of arbitrary paths and the robustness of the induced waves against defects. Eliminating the need for pre-etched topological protection paths on patterned substrates enhances flexibility in both manufacturing and application. This innovative scheme employs localized temperature control at the unit cell scale to achieve effects akin to approximately 10% geometric symmetry breaking, thereby significantly reducing precision manufacturing requirements. Moreover, localized thermal modulation holds considerable potential for improving modulation rates while minimizing energy loss.