Lanthanum Borosilicate Crystal Growth for Room-Temperature β-Phase Stability
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Solution Overview
Problem
The growth of large-scale high-temperature phase LaBSiO5 single crystals is hindered by phase transitions and poor crystal quality, limiting their use in photoelectric devices due to low size and instability at room temperature.
Innovation Solution
A growth method using a non-toxic composite flux system (La1-yLny)BO3—LiMoO4—SiO2—B2O3 with controlled doping of Ln3+ ions (Eu3+, Nd3+, Y3+, etc.) stabilizes the β-La1-yLnyBSiO5 crystal structure, allowing it to maintain a high-temperature phase at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a high-temperature phase LaBSiO5 crystal is grown using conventional flux methods, then the crystal can be obtained, but it undergoes phase transition at room temperature leading to severe stress release and poor crystal quality
Solution Approach 1:
The patent changes the chemical composition parameters by introducing rare earth ion doping (Ln3+) at controlled concentrations (0.02≤y≤0.25) into the LaBSiO5 crystal structure. This parameter modification stabilizes the high-temperature β-phase at room temperature, preventing the harmful phase transition to α-phase and eliminating the associated stress release and cracking issues.
Solution Approach 2:
The patent employs a composite flux system consisting of (La1-yLny)BO3—LiMoO4—SiO2—B2O3 with specific molar ratios, rather than using conventional single-component fluxes. This composite flux composition enables better control over crystal growth and phase stability, allowing the high-temperature phase to be maintained at room temperature with improved crystal quality.
2Volume of moving object
If conventional flux systems are used to grow LaBSiO5 crystals, then crystal growth is possible, but the crystal size remains extremely small (maximum 2 mm)
Solution Approach 1:
The patent modifies the flux system composition parameters by using a eutectic mixture of (La1-yLnym)BO3—LiMoO4—SiO2—B2O3 with optimized molar ratios. This composition change lowers the melting point and improves the flux's ability to dissolve and transport materials, enabling significant crystal growth to macroscopic sizes (centimeter scale) while maintaining phase stability.
Solution Approach 2:
The composite flux system acts as an intermediary medium that facilitates crystal growth by providing a suitable chemical environment. The flux components work together to dissolve raw materials, transport them to the growing crystal interface, and release them in a controlled manner, enabling large-scale crystal growth that would be impossible with conventional direct solid-state methods.
3Ease of manufacture
If toxic flux systems like K2Mo3O10—KF are used to grow LaBSiO5 crystals, then crystal growth can be achieved, but the process involves toxic materials
Solution Approach 1:
The patent changes the chemical composition of the flux system by replacing toxic components (K2Mo3O10, KF) with non-toxic alternatives ((La1-yLnym)BO3, LiMoO4, SiO2, B2O3). This substitution maintains the necessary flux functionality for crystal growth while eliminating the harmful toxic effects, making the manufacturing process environmentally friendly and safe.
Solution Approach 2:
The patent converts the potential harm of using conventional toxic fluxes into a benefit by deliberately selecting a non-toxic composite flux system that performs equally well or better in crystal growth. The replacement materials not only eliminate toxicity but also provide improved phase stability control and enable larger crystal sizes, turning a limitation into an advantage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables the growth of large-size β-La1-yLnyBSiO5 crystals with stable macroscopic symmetry, suitable for optical applications in lasers and terahertz fields, overcoming phase transition issues and enhancing fluorescence properties.
Implementation Method 1
phase transition of the β-La1-yLnymBSiO5 crystal may be suppressed by controlling a microscopic crystal structure of LaBSiO5 through a doping ion Ln3+; and the β-La1-yLnymBSiO5 crystal may be stabilized to room temperature without the phase transition
Implementation Method 2
The method produces large, stable β-La1-yLnymBSiO5 crystals with fluorescence properties, suitable for optical applications in lasers and terahertz fields
Data Source
AI summary
The present disclosure provides a growth method of a high-temperature phase lanthanum borosilicate crystal, where the high-temperature phase lanthanum borosilicate crystal is a β-La1-yLnyBSiO5 crystal prepared by a high-temperature flux method; a composite flux system is (La1-yLny)BO3—LiMoO4—SiO2—B2O3, and (La1-yLny)BO3, LiMoO4, SiO2, and B2O3 in the system have molar percentages of x1, x2, x3, and x4, respectively; 0<x1<0.3, 0.7≤x2<1, 0<x3<0.3, x1+x2+x3=1, x1:x4=2:1 to 4:1. In the present disclosure, a difficulty is overcome in the crystal growth of β-LaBSiO5 due to phase transition. The crystal is an optical function material that does not undergo the phase transition during annealing and can exist stably at room temperature. The crystal is widely used in laser, terahertz, and other fields.