## 1 Introduction  
Quartz fiber has excellent mechanical properties and high thermal stability, light weight, small thermal expansion coefficient [1; 2; 3; 4; 5; 6]. It is an ideal structural material to meet the requirements of high performance and light weight. It has become a commonly used material in the aerospace industry after metal alloys. Quartz fiber was not only light in weight, but also has good load-bearing capacity and maintains high stability [7; 8; 9]. In recent years, the outstanding mechanical and dielectric properties of quartz fiber have been used in aerospace high temperature radome system, which need high strength and toughness. However, it usually fails under the action of high load.  
Therefore, increasing the tensile resistance of quartz fibers performance was of great importance [10; 11; 12; 13]. Meanwhile, the demand for high thermal conductivity materials has been increasing. However, metal materials were susceptible to the environment, resulting in decreased performance, lifetime and substantial loss to the production and living [14; 15; 16]. In addition, the density of metal materials is too high to be ignored. Therefore, improving the thermal conductivity of quartz fiber is a hot topic of current research. Coating on quartz fibers is considered to be one of the most effective methods to prevent this in the current situation [17; 18; 19; 20; 21]. [PERSON] et al. evaluated the filament tensile strength of the bare and PBO-coated quartz fiber before and after 500 \({}^{\circ}\)C treated for 30 min. The flexural strength of PBO-coated fiber-reinforced composites is about 50 MPa [22]. [PERSON] et al. studied the tensile strength of the coated quartz fiber fabrics after calcination at 800 \({}^{\circ}\)C for 1 h. The tensile strength of quartz fiber fabric increased gradually with increasing MoSi2 contents in the coatings [23]. A number of techniques have been deposited in various types coatings onto fiber surface, including chemical vapor deposition, laser ablation, and dip coating. However, these methods have long experimental cycles, and it is still a huge challenge to achieve a uniform thickness coating on the fiber surface [24; 25; 26].  
We have previously prepared Al\({}_{2}\)O\({}_{3}\) coating on the continuous quartz fiber fabric by electrode plasma electrolysis in which the samples were not used as electrodes [27]. Based on the nonelectrode plasma electrolysis, we patented a novel technique, i.e., plasma electrolysis spray, in order to rapidly prepare a coating onto large-scaled fiber fabrics [28]. In the present paper, the plasma electrolysis spray was applied to successfully prepare Al\({}_{2}\)O\({}_{3}\) coatings on quartz fiber fabric. In this technology, plasma was generated by cathode, sprayed on the surface of quartz fiber with electrolyte under the action of thermal compression and mechanical compression, and the Al\({}_{2}\)O\({}_{3}\) coating was formed by physical and chemical reaction. The tensile properties of the quartz fibers treated for 30 min at 700 \({}^{\circ}\)C and then treated for 10 min at 800 \({}^{\circ}\)C were studied. The effect of the coating on the high thermal conductivity of quartz fibers was investigated. The formation mechanism of the Al\({}_{2}\)O\({}_{3}\) coating was preliminarily discussed [29; 30]. We believe that the thermally conductive quartz fiber with high thermal stability by plasma electrolysis spray will be widely used in flexible thermal shielding and insulation materials.