Silicide Coating for Aerospace Parts

Our goal was to 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.
==Project Definition==
===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 following is our Project Objective, as given by our sponsor:
"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."
Manipulate nozzles from 10 to 28 cm in lengthUniform inside surface coatings free of drips and runsSimple, automated operation
==Project Learning==
===Electrocoating Research===
Electrocoating is the process of using electrical forces to attract a coating to a surface, creating a uniform and controlled coating. Electrically charged particles are deposited out of a water suspension to coat an oppositely charged part. This process is self limiting so it will not build up layers of coating on already covered areas. This results in an even coating on all surfaces and geometries. 
There are four steps to this process. Pre-treatment: clean part of all foreign material and rinse thoroughly with deionized water. E-coat Bath: 80% deionized water 20% slurry. Deionized water acts as a carrier for the slurry to be deposited on part. Rinse: remove part from bath and rinse with deionized water.
Typical voltage ranges from 25-400 volts DC for this process.
===Nozzle Machining===
Medium Nozzle Progress	Medium Nozzle Progress	Medium Nozzle Progress	Medium Nozzle Progress	Medium Nozzle Progress	Medium Nozzle Progress
 	 	 	 	 	
Small Nozzle Progress	Small Nozzle Progress	Small Nozzle Progress	Small Nozzle Progress	Small Nozzle Progress	Small Nozzle Progress
 	 	 	 	 	
==Senior Lab Sub-Projects==
===Mass Analysis===
For this Mass Analysis Sub-Project we used the Electrocoating Method we researched to coat several aluminum samples and then compare their percent mass increases.
We used the following process:Cathodic Deposition Process:
Make bath consisting of 80% deionized water 20% paint
Pre-treat part with deionized rinse
Apply negative node to part and positive node to bath
Dip the part in the bath for given period of time at given voltage
Remove part from bath and rinse excess coating off with deionized water
Bake part 
Factors that control thickness of deposited coating:
Voltage (ranging from 20 to 400 volts DC)
Temperature of bath
Power supply: Fluke DC high voltage power supply
Voltage range 1V-3.5 kV
Current: 1amp
Electrocoating Setup
===Viscosity Analysis===
For the Viscosity Analysis Sub-Project we used a Ford #4 Viscosity Cup to determine the viscosity of the slurry and several other paints.
To perform this test, we simply filled the Ford #4 Viscosity Cup and timed the drain of the fluid.
Viscosity Test Setup
The following are the results from this test:
Viscosity Time Results
We also performed this test to try and find a surrogate coating with a viscosity similar to the slurry. To achieve this we mixed 150mL of Semi-Gloss Enamel with 100mL of water as a proof of concept for the ability to reduce the drain time. The result of this test is below:
Surrogate and Slurry Comparison
==Project Results==
===SolidWorks Nozzle Models===
Nozzle Models 	Nozzle Models 	Nozzle Models	Nozzle Models	Nozzle Models	Nozzle Models
300pxSmall Nozzle 	300pxMedium Nozzle 	 	 	 	
300pxLarge Nozzle 	 	 	 	 	
Sectioned Small Nozzle	Sectioned Large Nozzle	 	 	 	
===Completed Apparatus===
Completed Assembly
This assembly is capable of constant on-axis nozzle rotation as well as 180 degree rotation. These motions will create the conditions needed to accurately coat the inside of the nozzles.
===Stepper Motor Integration===
Stepper Motor Wiring
This is the circuit used for both the Nema-32 and Nema-34 Stepper Motors and their drivers.
The Nema-32 Stepper Motor was used for continuous rotation about the nozzle centerline.
The Nema-34 Stepper Motor was used for 180 degree rotation about the nozzle horizontal axis.
===Coated Nozzles===
Nozzle Models	Nozzle Models	Nozzle Models	Nozzle Models	Nozzle Models	Nozzle Models
Small Nozzle 	Medium Nozzle	 	 	 	
==Team Information==
Team Sprayers 	Team Sprayers 	Team Sprayers 	Team Sprayers	Team Sprayers	Team Sprayers
Picture 	Biography 	Discipline 	 	 	
Tygh Weyand 	I am from central Oregon and graduated from a very small town. I chose the University of Idaho for the small class size and the town of Moscow. I enjoy anything outdoors and especially like to hunt, fish, and ride dirt bikes. 	Mechanical Engineering	 	 	
Nick Ferguson 	My home town is Chehalis, Washington. My favorite subject areas in Engineering include Robotics and SolidWorks. Some of my hobbies are writing and playing video games. Other projects I have worked on include the MeArm Robot and the Studley Tool Chest Modelling Project. 	Mechanical Engineering	 	 	
Joe Morris 	I am from Spokane Washington. I work up in Alaska on a commercial fishing vessel during the summers and the rest of the year when not doing school I enjoy hunting,fishing, and mountain biking. 	Mechanical Engineering	 	 	
Trevor Livingston	In addition to Mechanical Engineering I am minoring in Physics. I fight wildfires for the Idaho Department of Lands in the summer. Current and past projects include designing a method to evenly coat the interior of rocket nozzles for ATI, solar powered pool heating and filtration system, turbo-machinery analysis on a centrifugal pump, FEA analysis on a rehabilitation exoskeleton.	Mechanical Engineering	 	 	
==Document Archive==
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