## 1 Introduction  
With the rapid development of technology, low-cost, lightweight, and reusable thermal protection materials for aerospace applications are in high demand to protect vehicles from damage under extreme conditions [1]. According to previous literature, carbon bonded carbon fiber composites (CBCF) have attracted much attention due to their low density and low thermal conductivity, and are considered a promising candidate for thermal insulation. CBCF is commonly prepared by vacuum or pressure filtration followed the pyrolysis method using chopped carbon fibers and phenolic resin (PR) as raw materials [2, 3]. Although numerous efforts have been made to research CBCF composites, the intrinsic problems of CBCF composites severely restrict them for practical application, namely weak mechanical and poor oxidation resistance under high-temperature conditions [4]. From the perspective of the mechanical property, the three-dimensional (3D) needed carbon fiber preform shows promise for overcoming the poor mechanical property of pristine chopped carbon fibers [4; 5]. In addition, the introduction of ceramic has been confirmed as an effective way to improve the high-temperature oxidation resistance of the composites up to now [6; 7]. Notably, the pristine 3D needed carbon fiber preform is too flexible to operate, and thus direct incorporation of the ceramic phase would result in the structural distortion of the pristine preform. In order to improve the operability of the pristine preform, incorporation of resin-derived carbon through a simple vacuum infiltration and pyrolysis process is an effective method similar to the preparation of CBCFs composites. In addition, compared with common phenolic resin (PR), boron-containing phenolic resin (BPR) presents better thermal stability at high-temperature due to much higher B-O bond energy than that of the C-O bond. Thus, it is reasonable to believe that introducing BPR-derived carbon into the pristine 3D needed carbon fiber preform through a simple method would enhance the high-temperature thermal stability of the composites compared to that of common PR pyrolyzed carbon [8]. From the ceramic point of view, polymer-derived ceramics (PDCs) have gained much attention, which could be attributed to their remarkable properties over conventional ceramics, such as low processing temperature and excellent properties, especially in thermal stability, high-temperature mechanics, and oxidation resistance [9; 10]. Among all PDCs, apart from the amorphous phase with low thermal conductivity, the low-cost silicon oxycarbide (SiC) ceramics possess inherent chemical durability, tunable mechanical and unusual high-temperature properties, which should be ascribed to its special structure, namely an anionic silica network, in which, two divalent O atoms are partially replaced by one tetravalent C atom [11; 12; 13]. Hence, SiC modified CBCF composites have been constructed and investigated by researchers [14], while there is no report on BPR-derived carbon modified 3D needed carbon fiber reinforced SiOC composites, which according to previous research have superior mechanical and high-temperature properties and could be used in high-temperature applications such as thermal protection systems. Moreover, the functional performance of PDCs after high-temperature annealing is also desired in addition to the structural properties, and the electromagnetic wave (EMW) absorption properties of PDCs have aroused lots of attention in recent years [15; 16; 17; 18; 19; 20; 21; 22; 23]. For example, [PERSON] et al. [21] successfully prepared porous PDC-SiC/Si\({}_{3}\)N\({}_{4}\) composites by the unidirectional freeze casting of Si\({}_{3}\)N\({}_{4}\)/camphene slurries with various polycarbosilane (PCS) contents. The results showed that the EMW absorption properties of the composites could be effectively controlled by the PCS content, whose minimum reflection loss (RLmin) was as low as \(-\)56.20 dB and the widest effective absorption bandwidth (EAB) was up to 7.00 GHz for the sample with 20 wt.% PCS.