Laser surface treatment for enhanced surface quality of Si3N4 + SiO2 wave-transparent ceramics

IF 5.1 2区材料科学 Q1 MATERIALS SCIENCE, CERAMICS

Ceramics International Pub Date : 2025-05-01 DOI:10.1016/j.ceramint.2025.01.483

Rajaram Kumar Gupta , Divya Rana , Dinesh Deva , Vijay Kumar Pal

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引用次数: 0

Abstract

Si₃N₄ + SiO₂-based wave-transparent ceramics are valued for their excellent mechanical strength and superior dielectric properties, making them suitable for radome applications. A recent study explored the production of these ceramics through compression molding of green pellets, followed by sintering (at 1500 °C). However, further improvements in mechanical properties without compromising dielectric performance are essential for use in harsh conditions. In this study, surface treatment using a CO₂ laser with a 10.6 μm wavelength was applied to green Si₃N₄ + SiO₂ ceramic compacts (GP), prepared by compression molding at 1912 MPa, to investigate changes in surface integrity, microstructure, and chemical composition before and after sintering. Thermal gravimetric analysis (TGA) confirmed that oxidation began at 700 °C, with a mass gain of 18 % up to 1500 °C. XRD and XPS confirmed Si₃N₄ and SiO₂ phases in the green pellets, with optimal laser parameters (10 W power, 15 mm/s) maximizing SiO₂ formation and inducing compressive residual stresses, of up to −128 MPa on green ceramic surface to −2045 MPa after sintering. This treatment significantly improved microhardness, increasing from 1566 ± 6.7 HV₀.₁ in untreated sintered samples to 1651 ± 7.1 HV₀.₁ in sintered, laser-treated samples. XRD results confirmed the formation of Si₃N₄, cristobalite-SiO₂, and Si₂N₂O phases in the laser-treated sintered ceramics which was also confirmed by the SEM micrograph. Line EDS (energy-dispersive spectroscopy) verified that the elemental composition of the laser-treated sintered surface remained consistent with that of the untreated sintered surface. These findings demonstrate that CO₂ laser treatment significantly enhances the mechanical properties of Si₃N₄-SiO₂ ceramics without compromising their dielectric performance, thereby greatly improving the material's suitability for radome applications in challenging environmental conditions.

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激光表面处理提高Si3N4 + SiO2波透明陶瓷表面质量

Si₃N₄+ SiO₂基波透明陶瓷因其优异的机械强度和优越的介电性能而受到重视，使其适用于天线罩应用。最近的一项研究探索了通过压缩成型绿色颗粒，然后烧结（1500°C）来生产这些陶瓷。然而，在不影响介电性能的情况下进一步改进机械性能对于在恶劣条件下使用是必不可少的。采用波长为10.6 μm的CO₂激光对1912 MPa压成型的绿色Si₃N₄+ SiO₂陶瓷制品（GP）进行表面处理，研究了烧结前后表面完整性、微观结构和化学成分的变化。热重分析（TGA）证实，氧化开始于700°C，在1500°C时质量增加18%。XRD和XPS证实了绿色颗粒中的Si₃N₄和SiO₂相，最佳激光参数（10 W功率，15 mm/s）最大程度地提高了SiO₂的形成，烧结后绿色陶瓷表面的残余压应力可达- 128 MPa至- 2045 MPa。显微硬度从1566±6.7 HV 0显著提高。1号在未处理的烧结样品中为1651±7.1 HV 0。在烧结，激光处理的样品。XRD结果证实了激光烧结陶瓷中存在Si₃N₄相、方石钡石- sio₂相和Si₂N₂O相，SEM显微图也证实了这一点。能谱能谱（EDS）验证了激光处理烧结表面的元素组成与未处理烧结表面的元素组成保持一致。这些发现表明，CO₂激光处理显著提高了Si₃N₄-SiO₂陶瓷的机械性能，而不影响其介电性能，从而大大提高了材料在具有挑战性的环境条件下的天线罩应用的适用性。

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来源期刊

Ceramics International 工程技术-材料科学：硅酸盐

CiteScore

9.40

自引率

15.40%

发文量

4558

审稿时长

25 days

期刊介绍： Ceramics International covers the science of advanced ceramic materials. The journal encourages contributions that demonstrate how an understanding of the basic chemical and physical phenomena may direct materials design and stimulate ideas for new or improved processing techniques, in order to obtain materials with desired structural features and properties. Ceramics International covers oxide and non-oxide ceramics, functional glasses, glass ceramics, amorphous inorganic non-metallic materials (and their combinations with metal and organic materials), in the form of particulates, dense or porous bodies, thin/thick films and laminated, graded and composite structures. Process related topics such as ceramic-ceramic joints or joining ceramics with dissimilar materials, as well as surface finishing and conditioning are also covered. Besides traditional processing techniques, manufacturing routes of interest include innovative procedures benefiting from externally applied stresses, electromagnetic fields and energetic beams, as well as top-down and self-assembly nanotechnology approaches. In addition, the journal welcomes submissions on bio-inspired and bio-enabled materials designs, experimentally validated multi scale modelling and simulation for materials design, and the use of the most advanced chemical and physical characterization techniques of structure, properties and behaviour. Technologically relevant low-dimensional systems are a particular focus of Ceramics International. These include 0, 1 and 2-D nanomaterials (also covering CNTs, graphene and related materials, and diamond-like carbons), their nanocomposites, as well as nano-hybrids and hierarchical multifunctional nanostructures that might integrate molecular, biological and electronic components.