Breaking strength tests on silicon and sapphire bondings for gravitational wave detectors

Abstract

Abstract. The realization of third generation gravitational wave interferometric detectors is under way. An important improvement in detector sensitivity can be obtained with the reduction of thermal noise by reaching a cryogenic stage. Two materials have been identified to perform efficiently at low temperature: silicon and sapphire. In this work the breaking strength of the silicate bonding that glues cylinders of silicon (Si) and sapphire (Al 2 O 3 ) has been investigated. All material combinations, flatness quality and orientations have been tested over time. Breaking strength between Si−Si and Si−Al 2 O 3 shows a value similar to that of fused silica, while Al 2 O 3 −Al 2 O 3 does not seem to be a promising combination.

Hydroxide catalysis bonding for astronomical instruments

“…First results of studies of the properties of hydroxide catalysis sapphire-sapphire bonds have been reported by Douglas et al [25], Dari et al [40] and Suzuki et al [42]. Studies of HCBs of silicon to silicon have been reported by van Veggel et al [32], Dari et al [40], Lorenzini et al [41], and Beveridge et al [38,39].…”

“…Examples of hydroxide solutions commonly used for bonding are potassium hydroxide (KOH) [9,13,21,25,33,36,40,41], sodium hydroxide (NaOH) [13,21,22,25] and sodium silicate solution [13, 16-21, 23-26, 28, 32, 34-39], which is a sodium hydroxide solution with a colloidal silicate (typically 10-14% NaOH, 27% SiO 2 ) dissolved in water. Other hydroxides that have been used in published research are caesium, lithium and rubidium hydroxide solution [13,21], sodium aluminate solution [25] and KOH with silica nanoparticles [27].…”

“…Studies of HCBs of silicon to silicon have been reported by van Veggel et al [32], Dari et al [40], Lorenzini et al [41], and Beveridge et al [38,39]. Most of the work reported in the literature focussed on the shear and tensile strength of bonds between silicon and sapphire, along with initial studies of the thermal conductance of bonds and scanning electron microscopy imaging of bonded interfaces.…”

Effect of heat treatment and aging on the mechanical loss and strength of hydroxide catalysis bonds between fused silica samples

“…The strength of hydroxide catalysis bonds between different materials such as fused silica, silicon, sapphire, ULE and zerodur have been studied previously [17,20,[31][32][33][34][35][36][37]. A summary of most of the results can be found in Ref.…”

Mechanical loss of a hydroxide catalysis bond between sapphire substrates and its effect on the sensitivity of future gravitational wave detectors

“…A feasibility study is underway for the use of hydroxide catalysis bonding in jointing crystalline materials in gravitational wave detector mirror suspensions [28][29][30][31][32][33]. Indium bonding is also being investigated; however, indium bonds would only be used in compressive load conditions [34,35].…”