Silicide Coating for Aerospace Parts

Problem Statement
Design, fabricate and test an apparatus that applies a uniform silicide coating (R512E) to the inside surface of a niobium based alloy (C-103) thrust chamber and rocket nozzle.

Specifications
Our first specification involves achieving the desired thickness of 120 microns. Our method for ensuring a consistent coating thickness concerns the final mass of the piece. If the our procedure can produce coated nozzles with the same final mass within a certain tolerance, it follows that these nozzles with have coatings of the same thickness, assuming the coating is even across the piece.

Our second specification involves the visual quality of the coating. In order to assess how even the coating is, the nozzles will be visually observed and compared with the desired visual qualities supplied by our sponsors. These qualities are no running, no bare spots, and no clumps; basically a visually even and smooth coating on the nozzle.

Our final specification is being able to replicate the above qualities on nozzles of various sizes, from 10-28 cm. In order to achieve this, our apparatus will be adjustable in order to accommodate nozzles of various size and geometry.

Objective
The refractory niobium metal alloy C-103, produced by ATI Specialty Alloys and Components, has a melting temperature of 2350±50°C, allowing for applications in space rocket nozzles. At operating temperatures up to 1482°C the alloy maintains yield strength greater than 48 MPa and exhibits excellent creep resistance. However, at high temperature the alloy reacts with oxygen to form a fast growing oxide layer that can consume the metal thruster.

To prevent this oxidation, a silicide coating (R512E) is applied. The current method of coating each nozzle uses a dip process with a liquid glaze that is then fired and cured in a furnace. This process can produce a poorly controlled coating thickness dependent on the individual rocket nozzle geometry. The process also does not allow for independently controlling the outer and inner coating thickness.

It is desirable to have a coating system that can accommodate a range of rocket nozzle sizes and produce a uniform coating thickness on the inside nozzle surface. Potential design direction include a fill and drain method where a fixture holds and seals a nozzle partly filled with glaze, while a computer controlled stage rotates and tilts the fixture in prescribed motion before draining. Glaze thickness can be estimated from weight addition and uniformity will be assessed by visual inspection.

MODBUS & EFB


The code to construct and send simple MODBUS data packets has been written and is currently undergoing tests on the hardware and VFD. With the code, a user has the ability to specify three different field-attributes that make up a MODBUS frame; node address, function code, and an array of data bytes to be sent. The code will automatically calculate the frame’s 16-bit CRC and append it to the end of a frame transmission. As a demonstration, I have attempted to form and send packets in attempt to cycle the VFD through it’s start-up procedures, accelerate to a reference, and then coast to a stop. In its current form, the demonstration is 100% successful (assuming the drive is set up appropriately).

RTDS Simulations
RTDS, REAL TIME DIGITAL SIMULATOR simulates the control-loop governing the existing system such that it responds as if it were a different, larger industrial power system like hydroelectric, steam, or gas. 2015 Byte Back RTDS Simulation



SEL 411L
We are using SEL-411L Relay Protection and Automation System for detecting the change in frequency in the system while applying load. SEL 411L allows us to capture any change happing over period of time for further analysis.